A Tale (and Tails) of Two Islands

Posted on March 15, 2013 by TMartin

After visiting Cumberland Island and Jekyll Island, our Barrier Islands class had entered its third day (Monday, March 11), and was now about to embark onto our third and fourth barrier islands of the Georgia coast. These islands were a Pleistocene-Holocene pair – St. Simons and Little St. Simons, respectively – and the latter was our primary goal. After all, Little St. Simons is a privately owned and undeveloped island, one of the few that has not been logged or otherwise majorly altered by those ever-nefarious and industrious post-Enlightenment humans. St Simons, though, had its own lessons to teach us, including a realization I had that ichnological factors (bivalve feces, specifically) had played a role in deciding the fate of European power struggles on the Georgia coast during the 18th century.

Just like the previous two posts, this one will be told through photos and captions, which I hope captures much of what my students and I learned during our times on these two islands. Just watch out for those tails.

Little St. Simons is a privately owned island, but is available for day tours of groups like ours that are led by their knowledgeable and friendly naturalists. Soon after arriving by small boats on the island and being greeted by the naturalists assigned to us, Laura (pictured) and Ben (you’ll see him soon enough). While there, Laura provided a brief introduction to the geological history of Little St. Simons: Holocene (probably only a few thousands years old), and rapidly gaining weight (sediment, that is) each year, supplied by the nearby Altamaha River.

Check out our air-conditioned field vehicles! Seeing that this is a field course, traveling this way was ideal for experiencing the island a bit more directly, yet without descending in a Heart-of-Darkeness or Lord-of-the-Flies sort of mode. Because that would be bad.

Little St. Simons has a healthy number of freshwater wetlands for such a small island (like this one), more closely resembling what used to be on the Georgia barrier islands before a few people decided that plantations and paper mills were great ideas.

Say, isn’t that an all-American bird? Yes, it is, but more importantly, it has a rather prominent trace next to it – a bald eagle nest – that is also occupied by a couple of young eagles. (Here, one is sticking its head out of the nest while being overseen by a protective parent.) Bald eagle nests are among the largest tree nests made by any modern bird, leading me to wonder what tree-dwelling dinosaur nests from the Cretaceous Period must have looked like.

Sorry folks, can’t get enough of bird traces on this island. Many of the tree trunks on Little St. Simons bear the horizontally aligned holes of yellow-bellied sapsuckers. These woodpeckers pierce tree trunks to cause the tree to bleed sap, which attracts insects, which get stuck, which get eaten by the sapsuckers. Sap + insects = tasty treat!

Armadillo tracks on a coastal dune at the north end of the island show just how far-ranging these mammals can get. Having only recently arrived to the Georgia coast since the 1970s, these prolific tracemakers are now on every island.

Near the armadillo tracks, also in the coastal dunes, were these mystery burrows. I had no idea what made these, as they were too small to be mole burrows, too big to be insect burrows, and too horizontal to be mouse burrows. Just a reminder that even the author of a 700-page book about Georgia-coast traces still has a lot more to learn.

Aw, look at this cute little baby alligator, which was near its momma in one of the freshwater ponds on Little St. Simons. I wonder where it came from originally?

Why, there’s where it came from: it’s momma’s nest! The arrow is pointing toward a now mostly collapsed alligator nest, which hatched the little tykes that are now in the nearby wetland. Alligator nests are composed mostly of loose vegetation that the mother collects and piles, enough that it will give off heat to incubate her eggs. Such nests have very poor preservation potential in the fossil record, but it is still very interesting to study how they disintegrate so rapidly.

Alligators (left) and birds (right, with one on her nest) last shared a common ancestor early in the Mesozoic Era, but here they are, working together to their mutual benefit. Great egrets and woodstorks nest on islands, which are guarded by large alligators, who are good deterrents to egg predators. (In a grudge match between an alligator and raccoon, who do you think would win?) As payment for this protection, alligators get an occasional chick falling out of the nest, a small evolutionary price for the birds to pay when compared to an entire clutch of eggs getting munched.

My, what a noisy tail you have! We were delighted to encounter this diamondback rattlesnake on one of the sandy roads of Little St. Simons, which urged us to approach it carefully, using a clearly audible warning and threat postures. (P.S. It worked.)

Our other guide, Ben, had an obviously deep affection for venomous reptiles, expressed first through some impromptu snake-handling. (No, he did not use his hands, nor did he speak in tongues. See that snake-handling device in his right hand?) Following our not-too-close encounter, he expounded on the ecological importance of rattlesnakes to the island, and related some interesting facts about rattlesnake behavior. Gee, you think the students might remember some of this lesson? (Personal note: Bring rattlesnakes into the classroom more often.)

At the south end of Little St. Simons is a very nice beach, and on that beach were – you guessed it – shorebird tracks. Here are some plover tracks, which could be from Wilson’s plovers, semi-palmated plovers, or some other species.

Sadly enough, our tour of Little St. Simons lasted only until 3:00 p.m., so we had some time on St. Simons to do a bit more learning. So I decided we would stop at Fort Frederica National Monument, on the north end of St. Simons Island. It turned out this was a educationally sound decision, especially when one of the rangers on duty – Mr. Ted Johnson (right) – volunteered to give our group a spirited and informative lecture about the former military importance of Fort Frederica. However, judging from the downcast looks on several of the students, I imagine they were already missing alligators, snakes, and shorebirds of Little St. Simons Island, and (of course) their traces.

The most obvious human traces at Fort Frederica are these “footprints” (foundations) of some of the buildings there in the 18th century. Established as a British outpost in Georgia to compete with the Spanish presence to the south, Fort Frederica was a thriving town as long as the military was there.

OK, you’ve no doubt read this far to find out how bivalve feces helped the English to defeat the Spanish in the mid-18th century and consequently gain a permanent foothold in Georgia (until those pesky colonials defeated them later that century, that is). See where the fort is located? Right on a point, facing a tidal channel, and with salt marsh on either side of it. Because the salt marshes are largely composed of feces and similar muddy ejecta of ribbed mussels and other invertebrates, these make for wonderfully gooey substrates. Such substrates tend to discourage rapid movement of ordinance-laden ground troops, which forced the Spanish to try other means for attacking the fort, which failed. Bivalve feces for the win! Traces rule! ¡En la cara, los conquistadores!

As our day neared an end, my students decided that an appropriate way to signal their pleasure with all they had learned was for them to give me the now-official fiddler crab salute, waving their mock claws in unison. We all plan to still use this when greeting on the Emory campus, which should thoroughly mystify other students, faculty, and especially administrators, the latter of whom will wonder if it is some sort of secret-society sign. (Which, in a sense, it will be. Be afraid. Be very afraid)

What island was next on our journey? My old favorite, Sapelo Island, just to the north of Little St. Simons and St. Simons, and as different from these as the preceding islands were from one another. Stay tuned for those photos and comments in just a few days, and get ready to learn.

Doing Field Work on a Developed Barrier Island

Posted on March 13, 2013 by TMartin

The second day of our Barrier Islands class field trip (Sunday, March 10), which is taking place along the Georgia coast all through this week, involved moving one island north of Cumberland (mentioned in this previous post), to Jekyll Island. I’ve been to Jekyll many times, but none of my students had, so they didn’t quite know what to expect other than what I had told them.

For one, I warned the students that Jekyll was not at all like Cumberland, which is under the authority of the U.S. National Park Service as a National Seashore. Consequently, it has a few residents, but is limited to less than 300 visitors a day. In contrast, many more people visit or live on Jekyll, and people have modified it considerably more. For example, Jekyll has a new convention center, regularly sized and miniature golf courses, a water park, restaurants, bars, and other such items absent during most of its Pleistocene-Holocene history. Another difference is that a ferry was need to get onto Cumberland, whereas we could drive onto Jekyll and stay overnight there in a hotel.

So why go there at all with a class that is supposed to emphasize the geology, ecology, and natural history of the Georgia barrier islands? The main reason for why I chose Jekyll as a destination for these students was so they could see for themselves the balance (or imbalance) between preserving natural areas and human development of barrier islands. Jekyll is one of those islands that is “in between,” where much of its land and coastal areas have been modified by people, but patches of it retain potentially valuable natural-history lessons for my students.

So what you’ll see in the following photos will focus on those more natural parts of Jekyll island, with some of the wonders they hold. However, this series of photos will end with one that will shock and horrify all. Actually, you’ll probably just shake your head and sigh with rueful resignation at the occasional folly of mankind, especially when it comes to managing developed barrier islands.

We started our morning like every day should start, with ichnology. Here, tracks of a gray fox, showing direct register (rear foot stepping almost exactly into the front-foot impression) cut between coastal dunes on the south end of Jekyll Island. The presence of gray foxes on Jekyll has caused some curiosity and concern among residents, with the latter emotion evoked because these canids are potential predators of ground-nesting birds, like the Wilson’s plover. Also, people have no idea how many foxes are on the island. If only we had some cost-effective method for detecting their presence, estimating their numbers, and interpreting their behavior. You know, like tracking.

My students show keen interest in the gray fox tracks, especially after I tell them to show keen interest as I take a photo of them. Funny how that works sometimes.

A Wilson’s plover! At least, I think it is.( Birders of the world, please correct me if this is wrong. And I know you will.) We spotted a pair of these birds traveling together on the south end of the island, causing much excitement among the photographers in our group blessed with adequate zoom capabilities on their cameras. Wilson’s plovers are ground-nesting birds, and with both gray foxes and feral cats on the island, their chicks are at risk from these predators. Again, if only we had some cost-effective method for discerning plover-cat-fox interactions. Tracking, maybe?

Here’s a little secret for shorebird lovers visiting Jekyll Island. Walk around the southwest corner of the island, and you are almost assured of seeing some cool-looking shorebirds along the, well, shore, such as these American oystercatchers, looking coy while synchronizing their head turns. These three were part of a flock of about twenty oystercatchers all traveling together, which I had never seen before on any of the islands. If you go walking on Jekyll, and know where to walk, you’ll see some amazing sights like this.

You were probably all wondering what American oystercatcher tracks look like, especially those made by ones that are just standing still. Guess this is your lucky day. Also notice the right foot was draped over the left one, causing an incomplete toe impression on the right-foot one. Wouldn’t it be nice to find a trace fossil just like this?

Black skimmers! We didn’t get to see them skim, but we still marveled at this flock of gorgeous shorebirds. These were in front of the oystercatchers, with an occasional royal tern slipping into the party, uninvited but seemingly tolerated.

Yeah, I know, you also wanted to know what black skimmer tracks look like. So here they are. Now you don’t need to use a bird book to identify this species: just look at their tracks instead!

You think you’re bored? Try being driftwood, with marine clams out there adapted for drilling into your dead, woody tissue. This beach example prompted a nice little lesson in how this ecological niche for clams has been around since at least the Jurassic Period, which we know thanks to ichnology. You’re welcome (again).

Beach erosion at the southernmost end of Jekyll gave us an opportunity to see the root systems of the main tree species there, such as this salt cedar (actually, it’s a juniper, not a cedar, but that’s why scientists use those fancy Latinized names, such as Juniperus virginiana). My students are also happily learning to become the scale in my photos, although I suspect they will soon tire of this.

Look at this beautiful maritime forest! This is what I’m talking about when I say “…patches of it [Jekyll Island] retain potentially valuable lessons in natural history.” This is on the south end of the island, and this view is made possible by walking just a few minutes on a trail into the interior.

Few modern predators, invertebrate or vertebrate, provoke as much pure unadulterated giddiness in me as mantis shrimp. So imagine how I felt when, through sheer coincidence, a couple walked into the 4-H Tidelands Nature Center on Jekyll, while I was there with my class, and asked if I identify this animal they found on a local beach. The following are direct quotations from me: “Wow – that’s a mantis shrimp!! Squilla empusa!! It’s incredible!!” I had never seen a live one on the Georgia coast, and it was a pleasure to share my enthusiasm for this badass little critter with my students (P.S. It makes great burrows, too.)

A stop at the Georgia Sea Turtle Center on Jekyll was important for my students to learn about the role of the Georgia barrier islands as places for sea turtles to nest. But I had been there enough times that I had to find a way to get excited about being there yet again. Which is why I took a photo of their cast of the Late Cretaceous Archelon, the largest known sea turtle. I never get tired thinking about the size of the nests and crawlways this turtle must have made during the Cretaceous Period, perhaps while watched by nareby dinosaurs.

At the north end of Jekyll, shoreline erosion has caused the beach and maritime forest to meet, and the forest is losing to the beach. This has caused the forest to become what is often nicknamed a “tree boneyard,” in which trees die and either stay upright or fall in the same spot where they once practiced their photosynthetic ways.

Quantify it! Whenever we encountered dead trees with root systems exposed, I asked the students to measure the vertical distance from beach surface to the topmost horizontal roots. This gave an estimate of the minimum amount of erosion that took place along the beach.

Perhaps a more personal way to convey the amount of beach erosion that happened here was to see how it related to the students’ heights. It was a great teaching method, well worth the risk of being photobombed.

Are you ready? Here it is, in three parts, what was without a doubt the traces of the day. Start from the lower left with that collapsed burrow, follow the tracks from left to right, and look at that raised area on the right.

A close-up of the raised area shows a chevron-like pattern, implying that this was an animal that had legs, and knew how to use them. Wait, is that a small part of its tail sticking out of the left side?

Violá! It was a ghost shrimp! I almost never see these magnificent burrowers alive and outside of their burrows, and just the day before on Cumberland Island, the students had just learned about their prodigious burrowing abilities (the ghost shrimp, that is, not the students). I had also never before seen a ghost shrimp trackway, let alone one connected to a shallow tunnel on a beach. An epic win for ichnology!

This may look like soft-serve ice cream, but I suspect that it’s not nearly as tasty. It’s the fecal casting of an acorn worm (Balanoglossus sp.), and is composed mostly of quartz sand, but still. These piles were common on the same beach at the north end of Jekyll, but apparently absent from the south-end beach. Why? I’m guessing there was more food (organics) provided by a nearby tidal creek at the north end. But I’d appreciate all of those experts on acorn worms out there to augment or modify that hypothesis.

This is how dunes normally form on Georgia barrier-island beaches: start with a rackline of dead smooth cordgrass (Spartina alterniflora), then windblown sand begins to accumulate in, on, and around these. Throw in a few windblown seeds of sea oats and a few other dune-loving species of plants, and next thing you know, you got dunes. Dude.

In contrast, here is how not to form dunes on Georgia barrier-islands beaches. Build a concrete seawall on the middle part of the island, truck in thousands of tons of metamorphic rock from the Piedmont province of Georgia, place the rocks in front of the seawall, and watch the beach shrink. So sad to see all of that dune-building smooth cordgrass going to waste. Anyway, the contrast and comparison you just saw is also what my students experienced by standing in both places the same day.

Jekyll Island gave us many lessons, but we only had a day there. Which islands were next? St. Simons and Little St. Simons, with emphasis on the latter. So look for those photos in a couple of days, in between new exploits and learning opportunities.

Cumberland Island, Georgia: Not a Barrier to Education

Posted on March 11, 2013 by TMartin

When learning about the natural sciences, there comes a time when just reading and talking about your topics in the confines of a classroom just doesn’t cut it. This semester, we had reached that point in a class I’m teaching at Emory University (Barrier Islands), in which we all needed a serious reality check to boost our learning. So how about a week-long field trip, and to some of the most scientifically famous of all barrier islands, which are on the coast of Georgia?

Last Friday, March 8, our excursion officially began with a long drive from the Emory campus in Atlanta, Georgia to St. Marys, Georgia. Fortunately, Saturday morning was much easier, only requiring that we walk across the street, step onto a ferry, and ride for 45 minutes to Cumberland Island. Cumberland was our first island of the trip, and the southernmost of the Georgia barrier islands. I have written about other topics there, including the feral horses that leave their mark on island ecosystems, the tracks of wild turkeys, and those marvelous little bivalves, coquina clams.

So rather than my usual loquacious ramblings, punctuated by whimsical asides, this blog post and others later this week will be more photo-centered and accompanied by mercifully brief captions. This approach is not only a practical necessity for proper time management while teaching full-time through the week, but also is meant to give a sense of the daily discoveries that can happen through place-based learning on the Georgia coast. I hope you learn with us, however vicariously.

After a 45-minute ferry ride to Cumberland Island, the students received a different sort of lecture when naturalist extraordinaire Carol Ruckdeschel – who is writing a book about the natural history of Cumberland Island – met with them and gave them a brilliant overview of the island ecology. She mostly talked with the students about the effects of feral animals on the island, then spent another hour with us in the maritime forest and through the back-dune meadows. It was a real treat for the students and me, and a great way to start the field trip.

A leaf-cutter bee trace! Despite my writing about these and illustrating them in my book, these distinctive incisions were the first I can recall seeing on the Georgia barrier islands. These traces were abundantly represented in the leaves of a red bay tree we spotted along a trail through the maritime forest, making for a great impromptu natural history lesson for the students.

A freshly erupted ghost shrimp burrow on the beach at Cumberland, in which the students were lucky enough to witness the forceful ejection of muddy fecal pellets by the shrimp from the top of its burrow. I mean, really: explain to me how the life of an ichnologist-educator can get any better than that?

The fine tradition a field lunch, made even more fine by the addition of fine quart sand to our meals, freely delivered by a brisk sea breeze. Did the sand leave any microwear marks on our teeth? I certainly hope so.

A student is delighted to test my ichnologically based method for finding buried whelks underneath beach sands, and find out that it is indeed correct. (Was there any doubt?) Here she is proudly holding a live knobbed whelk, which I can assure you she promptly placed back into the water once its photo shoot was finished for the day.

Just to join in the fun, other students decided my “buried whelk prospecting” method required further testing. Let’s just say this student did not disprove the hypothesis, but rather seemed to confirm it, and doubly so. It’s almost as if ichnology is a real science! (Yes, these whelks went back into the water, too.)

OK, enough about marine predatory gastropods (for now). How about some of the largest horseshoe crabs (limulids) in the world? We found a large deposit of their carapaces above the high-tide mark, some of which were probably molts, but others recently dead. Sadly, though, we did not see any of their traces. Bodies only do so much for me.

Where do dunes come from? Well, a mother and father dune love each other very much… No wait, wrong story. What happens is that dead cordgrass from the salt marshes washes up onto the beach, where it starts slowing down wind-blown sand enough that it accumulates. Now it just needs some wind-blown seeds of sea oats and other plants to start colonizing it, and next thing you know, dune. Dude.

Ah, a geological tradition in action: comparing actual sand from a real outdoor environment to the sand categories on a handy grain-size chart, and using a hand lens. It’s enough to bring a tear to the eyes of this geo-educator. Or maybe that was just the wind-blown sand.

Finally, something that really matters, like ichnology! This is a three-for-one special, too: sanderling feces (left), tracks, and regurgitants (right), the last of these also known as cough pellets. Looks like it had coquina and dwarf surf clams for breakfast.

Wow, more shorebird traces! The tracks are from a loafing royal tern, and it clearly needed to get a load off its mind before moving on with the rest of its day.

Tired of shorebird traces? How about a modern terrestrial theropod? Wild turkey tracks in the back-dune meadows of Cumberland were a happy find, leading to my grilling the students with the seemingly simple question, “What bird made this?” They did not do well on this, but hey, it was the first day, and at least no one said “robin” or “ostrich.”

Did somebody say “doodlebug?” This long, meandering, and collapsed tunnel of an ant lion (a larval neuropteran, or lacwing) tells us that this insect was looking for prey in all the wrong places.

Behold, tracks that bespeak of great, thundering herds of sand-fiddler crabs that used to roam the sand flats above the salt marsh. Where have they gone, and will they ever come back? Who knows where the males might be waving their mighty claws? Do the female fiddler crabs suffer from big-claw envy, or are they enlightened enough to reject cheliped-based hierarchies imposed upon them by fiddler-crab society? All good questions, deserving answers, none of which make any sense.

Yes, that’s right, feral horses are really bad for salt marshes. Between overgrazing and trampling, they aren’t exactly what anyone could call “eco-friendly.” My students had heard me say this repeatedly throughout the semester, and Carol Ruckdeschel said the same thing earlier in the day. But then there’s seeing it for themselves, another type of learning altogether.

And the day ended with beautiful ripple marks, beckoning from the sandflat below the boardwalk on our trip back onto the ferry. Even this ichnologist can appreciate the aesthetic appeal of gorgeous physical sedimentary structures.

What’s the next island? Jekyll, which is just north of Cumberland along the Georgia coast, visited yesterday. Stay tuned, and look for those photos soon.

Public Outreach via Ichnology: Traces for Kids

Posted on July 19, 2012 by TMartin

(This post is the second in a series discussing academic scientists and public outreach of their science, but with a focus on my recent experiences in using ichnology and paleontology for public outreach. The first of the series, introducing science outreach in general and some of its challenges for academic scientists, is here.)

One of the clichés of the environmentalism is to “think globally, act locally,” and the same principle applies well to public outreach done by scientists. For example, here in Atlanta, Georgia, I live near Fernbank Museum of Natural History. And by “near,” I mean I can ride my bicycle to it in 10-15 minutes from either home or my workplace at Emory University. Over my 20+ years in Atlanta, I’ve tried to cultivate a relationship with Fernbank, having done some informal consulting for them on exhibits, given public lectures about my research in ichnology and paleontology, shown some of my science-based artwork there, and otherwise done volunteer work that qualifies as public outreach.

Look, a real paleontologist who somehow escaped from his “ivory tower” (or stone house) and found time to talk with the public! This is a small visual sample of the fun I had this past Saturday at Fernbank Museum of Natural History, talking with children and their parents about dinosaur trace fossils. Why yes, those are Paleontologist Barbies (one of them quite famous) sitting in the box to the right of me. Do you have a problem with that? (Photograph by Ruth Schowalter.)

But one of my acknowledged deficiencies in public outreach with Fernbank and elsewhere has been sharing my science with kids. Full confession: I don’t have children. (As far as I know, that is. If I ever run for political office, I’ll find out for sure.) Moreover, nearly all of the students I teach are 18 to 22 years old, and I normally don’t have children around me through family, friends, or neighbors in everyday life. Thus most of my experience in communicating science at any level is with adults. This leaves me feeling a little handicapped and less confident about my abilities to adapt and use the unique set of skills needed for relating sometimes-complex scientific concepts to children.

Why should I bother getting bothered about this, especially in doing outeach with a local natural history museum? Well, a simple reality of natural history museums today is that their economic survival relies on children visiting them, and preferably (although not necessarily) with their parents in tow. Sure, educating the young has always been a role of natural history museums. But pitching science solely to kids while bypassing adults has become so pronounced in some museums that adults have begun complaining about the “infantilization” of museum exhibits.

Fernbank is not immune to this charge. For example, the traveling exhibit they have there now – The Scoop on Poop – is clearly aimed at viewers 10 years old and younger, and is inspired by a children’s book with the same title. To be fair, though, Fernbank hosting the Darwin exhibit from the American Museum of Natural History last year was a refreshing concession to adults who certainly felt like kids, filled with excitement and awe, while learning about the roots of evolutionary theory.

A study in contrasts of traveling exhibits that have been to Fernbank Museum. Above, here’s part of the sign that greeted visitors to the Darwin exhibit, shown there September-December 2011…

…and here’s the sign welcoming people to the Scoop on Poop exhibit, showing there now. Gee, do you think each was intended for a different audience?

So it was with a mixture of mild trepidation, but also eagerness, that I welcomed an opportunity for outreach with kids and their parents last Saturday, July 14. One of my friends who works at Fernbank asked me several weeks ago if I’d be interested in participating in a museum event they organized for July 14-15, called “The Scoop on Dinosaurs.” In this event, Fernbank put together a range of dinosaur- and other science-related activities and programs for kids, but of course also designed it with the assumption that these kids would be accompanied by parents or other adults. The problem was, all of the planned activities lacked a real, practicing scientist, let alone a paleontologist. And seeing that I’m one of the few paleontologists in the Atlanta area, I live close by, and I enjoy doing public outreach, it made sense for me to participate.

After discussing it with my Fernbank friend, we decided that a simple “meet the paleontologist” format would work best, with me sitting at a table and talking informally with people about one of my research topics – dinosaur trace fossils – as they dropped by. I also thought it would be good to have a few props, and ones that would provoke inquiry-based learning, or what educators used to call “thinking.”

For example, I brought with me two sets of dinosaur bones, one of which was noticeably denser than the other. (And by the way, real bones are essential, so the kids could say and remember when they held real dinosaur bones.) These differences, which engaged a sense other than sight, lent well to the question, “Why is one bone heavier than the other, even though they’re the same size?,” followed by a discussion of the preservation of dinosaur bones.

Whoa, dinosaur bones! The darker dinosaur bone on the left is noticeably heavier than the lighter-colored one on the right, which the kids could feel for themselves right away when they put one in each hand. After they noticed this, I asked them why, and next thing you knew, we were having a scientific discussion.

Of course, because I’m ichnologist, you just knew some traces and trace fossils were somehow going to be involved in this, too. Sure enough, my friends at Fernbank printed out and laminated the following two photographs of mine, which I used to introduce the concept of dinosaur tracks to the kids. But rather than just blabbing on about each track, I showed them the photos and asked “Which one is the dinosaur track, which one is the bird track?” One track was from a modern sandhill crane (Grus canadensis) made on a Georgia barrier island, whereas the other was from a non-avian Cretaceous theropod dinosaur.

Which is the bird track and which is the dinosaur track? It’s kind of a trick question, but one that also introduces the concept that questions can have multiple right answers, and those answers lead to more questions and deeper meaning. And just in case you were wondering, the track on the left is from a theropod dinosaur, preserved in Early Cretaceous rocks that are about 105 million years old, and the one on the right is from a modern sandhill crane. (Both photographs by Anthony Martin, the left one taken in Victoria, Australia, and right one taken on St. Catherines Island, Georgia.)

For the more shy kids, I asked them to just point to the one they thought was the dinosaur track, and assured them that it was OK to be wrong, because being wrong is also part of science. So what was fun about this exercise was how they could be right no matter which they picked. If they pointed to dinosaur track, I would tell them they were right. But if they instead pointed to the modern sandhill crane track, I smiled and said, “You’re right, but it’s from a modern dinosaur, because birds are dinosaurs, too.”

This revelation led to a short explanation of how some dinosaurs are still around as birds, even if all of the other dinosaurs went extinct 65 million years ago. (Most of the kids already knew this, but I’m not so sure all of their parents did.) They also could clearly see that the tracks, which were very similar in size and shape, comprised one piece of evidence showing the relatedness of these two animals, even though they were separated by more than 100 million years. With a few of the older kids, we even talked some about how they were able to distinguish the fossil track from the modern one. (“That looks like a rock, and that looks like sand,” some of them said. Couldn’t have said it better myself.) What was really fun about this approach was to see how much the kids’ parents learned from this ichnologically based exercise, too. In other words, this wasn’t just done with children in mind.

Another simple trace-fossil-oriented quiz came from a photo of a 75-million-year-old dinosaur coprolite. Only I didn’t tell them it was a coprolite; instead, I told them what was in it (bits and pieces of plants), that my hand was in the picture (showing the size of the rock), and that the rock was a type of dinosaur trace fossil.

What’s this? It has bits and pieces of plants in it, it’s big (there’s my hand for scale), and it came from a dinosaur. If you said “paleo-puke,” that’s not bad, but you’re thinking of the wrong end of the dinosaur. It’s a coprolite, probably from a hadrosaur (like Maisaura), and is from the Late Cretaceous Two Medicine Formation of northwestern Montana.

With just those few clues, sometimes aided by my holding my nose, some kids actually figured it out (“DINOSAUR POOP!”), and even those who didn’t immediately get it were delighted with their answer after guiding them with just a few more questions. There’s probably something about their having recently learned proper toilet habits (reinforced daily) that makes feces loom large in a child’s imagination. So linking such traces to dinosaurs makes those feces even bigger, smellier, and hence more memorable.

With regard to other academic paleontologists who do public outreach, several parents mentioned that their kids regularly watch the TV show Dinosaur Train on PBS, and that’s how their children were learning about paleontology (or, more narrowly, just dinosaurs and pterosaurs). Although I’ve only seen a few clips from this show, I knew its host is also a real, academically trained research paleontologist with a Ph.D., Dr. Scott Sampson, sometimes known simply by the kids as “Dr. Scott.” So I made sure to tell these parents how fantastic it was to see an academic paleontologist with such credentials teaching paleontology in a children’s show. In other words, I was trying to counter the “Sagan effect,” while helping to dissuade parents from the notion that academic scientists are all disengaged from the public. (Maybe we paleontologists could call it the “Sampson effect.”)

Dr. Scott Sampson, an academic paleontologist who went on to do something a little different in his career, which was to become a science communicator with a recent focus on teaching paleontology to kids. Yet he still does peer-reviewed research on dinosaurs, meaning the two are not mutually exclusive. And you know what? The rest of us academic paleontologists think that’s cool.

Of course, I had lots of kids say, “I want to be a paleontologist!” Not wanting to crush their dreams with tales of pessimistic woe from academia (see my previous post if you need a big downer on that), I instead saw this as a chance for them to learn science in upcoming years, regardless of whether they become paleontologists or not. So advice I gave to those kids included (in particular order):

Get outside as much as possible. Although I’m not an overly fervent acolyte of Richard Louv and his “get kids in nature” movement, I do agree with the basic premise that kids need to connect more directly with nature by simply getting their little butts outside. From what I understand, “Dr. Scott” preaches the same message, so it’s good for kids to hear this coming from paleontologists, who do lots of their best work outside.
When you’re not outside, read as much as possible. Although, now that I think about it, I should have advised them to read outside.
Take lots of math classes. These kids represent the future, and the future of paleontology means more computer applications and more quantification of our data. So they can’t think about doing paleontology without also thinking about how math will be used in that science. Even though some kids wrinkled their tiny noses at me when I said “lots of math,” they got the message.
Take lots of science classes. And for the science classes, I told them that they’d better take geology, but also biology and chemistry. (I’m not sure if I mentioned physics, but maybe that was my way of getting back at fictional physicist Sheldon Cooper for what he’s said about geology.)

Yes, I know, all of this sounds wonderful, in a self-congratulatory, back-patting sort of way. Yay me! Nonetheless, while doing this outreach, I remained conscious of how I also fulfill a tenacious stereotype in paleontology. This typecasting has been discussed by fellow paleo-bloggers Victoria Arbour (here) and Brian Switek, the latter dubbing it the “male and pale” syndrome. It’s a syndrome exemplified by documentary filmmakers who pretend that the entire paleontological community is composed of middle-aged men of European descent, or, to throw in some diversity, older men of European descent.

Considering I live in an ethnically diverse place – Atlanta is more than 50% African-American, for starters – I’m reminded daily that my face doesn’t match those of most kids around me (and it’s not just the beard). This was certainly true for those kids and parents who stopped by to see me on Saturday: it was a rainbow of ethnicities totally unlike anything I experienced as a kid growing up in Indiana in the 1960s. But for here in Atlanta and many major metropolitan areas in the U.S. and around the world, this is normal. So if paleontologists who look like me plan to do public outreach, they have to be mindful of this reality, get educated about other ethnicities, and adjust accordingly. In this respect, I’ve been enlightened through working some with Emory’s Center for Science Education, which has had great success in implementing a variety of programs working to increase minority participation at all levels in STEM (science, technology, engineering, math) in the Atlanta area.

I’m also sensitive to the gender gap in perceptions of paleontologists, or the expectation that all paleontologists will be male, even as the demographics in our profession start to approach equity (though admittedly, we still have a long ways to go). So I made sure, after showing them the photo I had taken of a dinosaur coprolite from Montana and discussing how feces get fossilized, to tell them that the paleontologist who actually studied those coprolites was Dr. Karen Chin. Plus, I pointed toward the nearby Scoop on Poop exhibit and said they should go in there and watch Dr. Chin speak about her research on coprolites in several videos there. (Karen, if you’re reading this, thanks for your virtual help in being a cool role model!)

Dr. Karen Chin, the acknowledged world expert on dinosaur coprolites, who also doesn’t look like me (and that’s a good thing for both of us.) Here she is holding up one of her research subjects, which fortunately is sufficiently fossilized for her to gesture without getting any of it on her or the person behind the camera. Oh, and sorry if my photo taken from a video in The Scoop on Poop exhibit violates some sort of copyright, but I did it for the children. So there.

So it was with great joy and satisfaction that I’ll note my mere two hours of public outreach filled me with hope for the future. Many kids, accompanied by proud parents, stopped by to meet a “real paleontologist” and chat about, well, paleontology. Although I should have taken data, tabulated results, and analyzed them for significance, of the kids who said, “I want to be a paleontologist,” I recall the gender ratios were about 50:50. Probably my favorite brother-sister pair consisted of the brother who wants to be a paleontologist and the sister wants to be a marine biologist. (Making it even better, their dad was very pleased with the prospect of having two scientists in the family.)

I was also occasionally astonished at how knowledgeable some of the kids were. For example, one 10-year-old girl asked me whether one of the dinosaur bones I had brought was from a hadrosaurine or lambeosaurine dinosaur, which we then discussed (based on the extremely scanty evidence, that is). Her mother wore a face-splitting grin as she watched this exchange between her daughter and me, and other kids stood by in awe: looking at the girl, not me. Now that’s peer teaching!

Her (left): “What? You really think the phylogenetic distinction between the hadrosaur clades is based on THAT plesiomorphy?” Her sister (right): “Yeah, who taught you cladistics anyway?” Me: “Um, uh, OK. Say, have either of you ever watched Dinosaur Train?”

Will I do this kind of public outreach again? Sure, and Fernbank can certainly count on me doing more such programs with them in the future. From this experience I also learned that “dinosaurs and kids” as a frame for science education, whether at natural history museums or elsewhere, is a fountain that apparently never goes dry. But even better, I can still use my academic research specialty – ichnology – to provide a different perspective on dinosaurs specifically and science in general, for children and parents alike.

Public outreach in paleontology with kids can be fun and rewarding, given the right setting, preparation, and attitude. Meanwhile, just behind me, Gigantosaurus is apparently chasing Argentinosaurus, giving a whole new twist to the term “ankle biter.” (Photograph by Ruth Schowalter, taken at Fernbank Museum in Atlanta, Georgia.)

Further Reading

None for now. Go outside instead.

Marine Moles and Mistakes in Science

Posted on June 25, 2012 by TMartin

A first day of field work in the natural sciences can be expected to hold surprises, no matter what type of science is being attempted. Sometimes these are unpleasant ones, such as finding out the fuel gauge in your field vehicle – which you are driving for the first time, and in a remote place – doesn’t work. Other times, you make a fantastic discovery, like a new species of spider, a previously undocumented invasive plant, or a fossil footprint. But sometimes you see something that just makes you scratch your head and say, “What the heck is that?”, or more profane variations on that sentiment.

What is this long, meandering ridge making its way through a beach to the high tide mark on Sapelo Island, Georgia, and what made it? If you’re curious, please read on. But if you already know what it is, then you know a lot more than I did the first time I saw something like this. (Photograph by Anthony Martin.)

The last of those three scenarios happened to me on Sapelo Island, Georgia, in June 2004. My wife Ruth was with me, and we had just arrived on the island the previous afternoon, having stayed overnight at the University of Georgia (Athens) Marine Institute, or UGAMI. We decided that our first full morning in the field would be at Nannygoat Beach on the south end of Sapelo, which is a 5-minute drive or a 20-minute walk from the UGAMI.

We drove a field vehicle there (the gas gauge and everything else worked), parked, and took the boardwalk over the coastal dunes. Our elevated view from the boardwalk afforded a good look at many insect, ghost crab, bird, and mammal tracks made in the early morning. Circular holes punctured the dunes, made by ghost crabs (Ocypode quadrata). Sand aprons composed of still-moist sand were next to these burrow entrances, bearing crisply defined ghost-crab tracks, although early-morning sea breezes had already started to blur these.

At some point after walking onto the beach, though, we saw traces that we had not noticed in previous visits to Sapelo, and ones I have rarely seen there or on other Georgia barrier islands since. These oddities were meters-long, slightly sinuous to meandering ridges, about 15-20 cm (6-8 in) wide, extending in the sandy areas from the dunes through the berm and down to the high-tide mark, where they ended abruptly.

Same meandering ridge shown in the first photo, but viewed from the high-tide mark, showing how it connects with the primary dunes. Note how a few holes are punched in the part near me: more about those soon. (Photograph by Anthony Martin, taken on Sapelo Island, Georgia. P.S.: My wife Ruth is the scale in both photos, fulfilling one of the top 10 signs that I might be a geologist.)

Although a few ridges crossed one another, they rarely branched, and if they did, the branches were quite short, only about 10-15 cm (4-6 in). When we followed them to the dunes, they seemed to originate from some unseen place below the sandy surfaces. We investigated further by cutting through some of the ridges to see what they looked like inside. They turned out to be mostly open tunnels with circular cross sections about 5 cm (2 in) wide, slightly wider than a U.S. dollar coin. They were mostly hollow, and only occasionally did we encounter a plug of sand interrupting tunnel interiors. This supposition was backed up by ridges that had collapsed into underlying voids. A few of the ridges stopped with a rounded end the same diameter as the ridge, or as a larger, raised, elliptically shaped “hill.”

Ridge with quite a bit of meander in it. Check out the short branch toward the top right, where the tracemaker must have changed its mind and backed up, then continued digging toward the viewer. Scale = 15 cm (6 in). (Photograph by Anthony Martin, taken on Sapelo Island, Georgia.)

Two separate ridges intersecting, caused by one crossing the other, resulting in “false branching.” Also notice the partial collapse of sand into underlying hollow tunnels and how one of the ridges ends in a rounded mound. Scale = 15 cm (6 in). (Photograph by Anthony Martin, taken on Sapelo Island, Georgia.)

A short ridge ending in a raised, elliptical “hill,” connected to a partially collapsed tunnel that is not otherwise evident as an elevated surface. Same scale as before. (Photograph by Anthony Martin, taken on Sapelo Island, Georgia.)

Ruth and I agreed that these tunnels were burrows, instead of some random features made by the winds, tides, or waves. But by what? Clearly their makers were impressive burrowers, capable of digging through meters of sand. Their bodies also were probably just a little narrower than the burrow interiors, which helped us to think about body sizes. Then we considered where we were – dunes and beach – and what animals were the most likely ones to burrow in these environments.

A process of elimination – determining what they were not – was a good way to start figuring out their potential makers. For example, no way these burrows were from insects, such as beetle larvae, ant lion larvae, or mole crickets, because they were just too big. Insects also have a tough time handling salinity, so once they got to the surf zone with its saturated, saline sand, they would have had problems, or (more likely) an aversive reaction and turned around immediately instead of plowing ahead.

Insect burrow in coastal dune sand, made by a small beetle. Look at both the form and scale, and you’ll see this is not a match for what we were seeing. Scale in centimeters. (Photograph by Anthony Martin, taken on Cumberland Island, Georgia.)

Small mammals, like beach mice (Peromyscus polionotus), didn’t seem like good candidates either. Beach-mouse burrows are totally different from what we were seeing, and their burrows do not run all of the way down to the intertidal zone. Mice, like insects, also don’t like marine-flavored water; even if they might be able to temporarily tolerate it, they wouldn’t continue to burrow through moist, salty sand.

A beach-mouse burrow, with their tracks coming and going. Either the mice dug this burrow, or they occupied an abandoned ghost-crab burrow. Regardless, this also doesn’t match our mystery traces. Scale in millimeters. (Photograph by Anthony Martin, taken on Little St. Simons Island, Georgia.)

This led to an initial hypothesis that these burrows were from one of the most common larger burrowing animals in the area, and one comfortable in dune, berm, and beach environments with saturated, salty sand. These could only be from ghost crabs, I thought, an explanation supported by undoubted ghost crab burrows that perfectly intersected these tunnels, accompanied by undoubted ghost-crab tracks.

Ghost-crab burrows intersecting tunnels, accompanied by lots of ghost-crab tracks. Wow, that’s really convincing circumstantial evidence, wouldn’t you say? (Photograph by Anthony Martin, taken on Sapelo Island, Georgia.)

End of story, right? Well, no. I and a lot of other scientists have said this before, but it bears repeating: part of how science works is that in its practice we do not prove, we disprove. I somehow knew the “ghost crab burrowing horizontally through meters of sand from the dunes to the beach” hypothesis was a shaky one, and it bothered me that it just didn’t seem right. So I started reading as much as possible about ghost-crab burrowing behaviors. I thought I already knew a lot about this subject, but nonetheless was willing to acknowledge that there might be some holes in my learning (get it – holes?) that needed filling (get it – filling? Oh, never mind).

The gentle reader probably surmised what happened next. That’s right: not a single peer-reviewed reference mentioned ghost crabs digging meters-long shallow tunnels from the dunes to the beach. So either I was wrong, or I had documented a previously unknown and spectacular tracemaking behavior in this very well-studied species. A single cut by Occam’s Razor simply said, “You’re wrong.”

You thought I made long horizontal burrows that go all of the way from the dunes to the surf zone? Wow, you primates are dumber than I thought. (Photograph by Anthony Martin, taken on Sapelo Island, Georgia.)

If not a ghost crab then, what else could make meters-long horizontal burrows of the diameter we had seen? This is when I began to reconsider my original rejection of moles as possible tracemakers.

So what am I: chopped liver? (Photograph from Kenneth Catania, Vanderbilt University, and taken from Wikipedia.org here.)

Here’s what was the most interesting about this mistaken interpretation: it was made because of where we were. In other words, our initial mystification about these traces stemmed from their environmental context. Had we seen these burrows winding down a sandy road in the middle of a maritime forest on Sapelo Island, we would not have hesitated to say the word “mole.” Yet because we saw exactly the same types of burrows in coastal dunes and beaches, we said, “something else.”

A long, meandering mole burrow in the sandy road going through a maritime forest on the north end of Sapelo Island. So if you see a burrow like this in the forest, you instantly say “mole.” But if you see it on the beach, you say, “Um, uh, duh…must be something else!” My tracks (size 8 1/2, mens) and 15 cm (6 in) photo scale for, well, scale. (Photograph by Anthony Martin.)

Another long, meandering ridge ended in a rounded “hill,” a trace that no one would hesitate to call a mole burrow, especially because it’s in the middle of a maritime forest. (Photo by Anthony Martin, taken on Sapelo Island, Georgia.)

A trip back to the literature further confirmed the mole hypothesis while also serving up a big slice of humble pie. I was embarrassed to find that these same burrows were described and interpreted as mole burrows in an article published in 1986. Even more mortifying: my dissertation advisor (Robert “Bob” Frey) was the first author on the article; it had been published while I was doing my dissertation work with him; and I had read the article years ago, but didn’t remember the part about mole traces. It was like these burrows were saying to me, “Go back to school, young man.”

OK, so these are mole burrows. Case closed. Now that we’ve identified them, we can stop thinking about them, and go on to name something else. But that ain’t science either, is it? This one answer – mole burrows – actually inspires a lot of other questions about them, which could lead to heaps more science:

• Which moles made these burrows? The Georgia barrier islands have two documented species of moles, the eastern mole (Scalopus aquaticus) and star-nosed mole (Condylura cristata). Of these two, eastern moles are relatively common on island interiors, whereas star-nosed moles are either rare or locally extinct from some of the islands. But star-nosed moles are also more comfortable next to water bodies and seek underwater prey. So could these traces actually signal the presence of star-nosed moles in dune and beach environments? Frey and his co-author, George Pemberton, originally interpreted these as eastern mole burrows, but they also didn’t eliminate the possibility of star-nosed moles as the tracemakers, either.

• What is the evolutionary history of moles on the Georgia barrier islands? Are these moles descended from populations isolated from mainland ones 10,000 years ago by the post-Pleistocene sea-level rise, or do they represent more modern stock that somehow made its way to the islands? A genetic study would probably resolve this issue, but who the heck is going to compare the genetic relatedness of moles from the Georgia barrier islands to those on the mainland?

• What were they eating? Moles don’t just burrow for the exercise, but for the food. While burrowing, they are also voraciously chowing down on any invertebrate they encounter in the subsurface. But what would they eat in beach sands? As many shorebirds know, Georgia beaches are full of yummy amphipods, which would likely more than substitute for a mole’s typical earthworm- and insect-filled diet in terrestrial environments. Yet as far as I can find in the scientific literature, no one has documented mole stomach contents or scat from coastal environments to test whether these small crustaceans are their main prey or not.

• What happened to these moles once their burrows got to the surf zone? Did they turn around and burrow back, or did they go for a swim in the open ocean? The latter is actually not so far fetched, as moles are excellent swimmers, especially star-nosed moles. But how often would they do this?

• Just how common (or rare) are these burrows in beaches? Just because I just perceive these burrows as rare could be an example of sample bias. Yes, I wrote an entire book about Georgia-coast traces and tracemakers and have done field work on the islands since 1998. But I don’t live on the Georgia barrier islands, nor have I spent more than a week continuously on any of them. Keenly observant naturalists who live on the islands or otherwise spend much time there could better answer this question than me. I suspect they’re actually much more common than I originally supposed, and now look for them to photograph or otherwise document whenever I go back to any of the islands.

• Would such burrows preserve in the geologic record? Probably so, especially if they were made in dunes and filled with a differently colored or textured sand. But I’ll bet that nearly every paleontologist or geologist would make the same mistake I did, and reach for a burrowing marginal-marine crab or some other invertebrate as the tracemaker.

Geologists would be further fooled if fossil mole tunnels were intersected by genuine ghost-crab burrows, which would constitute a great example of a composite trace made by more than one species of animal. But why did the crabs burrow into the mole tunnels? Because it was easier. After all, the moles left hollow spaces and loosened sand over wide areas, practically begging ghost crabs to exploit these disturbed areas.

Anyway, I doubt many geologists would think of a small terrestrial mammal as a tracemaker for such burrows in sedimentary rocks formed in marginal-marine environments, although I’d love to be proved wrong on this. I’m hoping my writing about it here will help to prevent such confusion, and that whoever benefits from it will buy me an adult beverage as thanks.

In summary, this example of making a crab burrow out of a mole tunnel thus serves as a cautionary tale of how where we are when making observations in the field can influence our perceptions. But it also goes to show us how our wonderment with what we observe in natural environments can be renewed and encouraged by daring to be wrong once in a while, and learning from those mistakes.

Further Reading

Frey, R.W., and Pemberton, S.G. 1986. Vertebrate lebensspuren in intertidal and supratidal environments, Holocene barrier island, Georgia. Senckenbergiana Maritima, 18: 97-121.

Gorman, M.L., and Stone, R.D. 1990. The Natural History of Moles. University of Chicago Press, Chicago, Illinois: 138 p.

Harvey, M.J. 1976. Home range, movement, and diel activity of the eastern mole, Scalopus aquaticus. American Midland Naturalist, 95: 436-445.

Henderson, R.F. 1994. Moles. Prevention and Control of Wildlife Damage, Paper 49, University of Nebraska, Lincoln: D51-58. (Entire text here.)

Hickman, G.C. 1983. Influence of the semiaquatic habit in determining burrow structure of the star-nosed mole (Condylura cristata). Canadian Journal of Zoology, 61: 1688-1692.

The Ichnology of Peeps

Posted on April 6, 2012 by TMartin

Once a year, around Easter time, an attentive beachcomber might notice the unusual traces of a migratory animal on the sands of the Georgia barrier islands. Based on a few clues, its traces point toward five identically sized and conjoined tracemakers, indicating some sort of obligatory group behavior.

Eyewitnesses swear these tracemakers – nicknamed “peeps” – possess a few superficial avian qualities, yet they lack many of the anatomical traits we normally associate with birds, such as, well, wings and legs. Indeed, they apparently have flat ventral surfaces, which with their forward movement along beach sands cause trails, rather than trackways.

Peep trail, observed on berm of Nannygoat Beach, Sapelo Island, Georgia. Oddly enough, this trail shows both a sudden start and end, almost as if the peeps were placed and removed from the surface, respectively.

As a result, peep trails – which are sometimes sinuous, but always harmonious – consist of five parallel grooves, each spaced equally and separated by six ridges, four on the interior of the trail and one on each side. Lateral movements along the length of a peep trail can vary the height of these ridges, depending on whether the peeps are banking to the right or left as they turn.

Although flying ability in peeps has only been inferred on the basis of their possible avian affinity, peep traces show only very brief periods of airborne activity. These traces indicate a somewhat clumsy strategy when approaching ground surfaces, culminating in abrupt vertical descents best described to laypeople as “crashing.” Ideally, all five peeps leave impressions of their cranial anatomy, which includes rudimentary beaks and foreshortened premaxillas. I have no idea if this facial configuration reflects acquired characteristics – caused by frequent crashes – or are more attributable to their original genotype.

Peep landing trace, in which impressions of the anterior anatomy are preserved. Note the short beak marks and rounded dorsal portion of the torso, but with a thin shelf close to the ventral surface. Sand ridges around the impressions suggest the tracemaker bounced after landing.

Peep resting traces are sometimes subtle, owing to their light weight, which according to some sources is about 85 grams (3.0 ounces) in total, or 17 grams per peep. In such instances where their resting traces are recognized, though, peep ventral anatomy is more clearly discernible. Interestingly, the anterior portion of their bodies is rounded and broad, but tapers into a blunt, narrow posterior with a possible upturned tail, the latter suggested by a thin groove bisecting the dorsal part of this posterior mark.

But perhaps the puzzling aspect of these traces is their lack of feather impressions. This evidence shows that peeps, despite their inferred avian affinity, must have become secondarily featherless, despite a long history of descent from non-avian dinosaurs.

Peep resting trace, barely noticeable owing to the light weight of its tracemakers, yet still apparent through its typical overall five-part form.

As is typical with resting traces, these are often connected directly to traces of other behaviors, such as locomotion or burrowing. Indeed, peep resting traces sometimes segue into or out of shallow burrows, which again have five impressions on their bases. Burrowing is presumably an adaptive strategy to avoid predation, implying delectable qualities.

A peep resting trace that is also a burrow, and connecting to an exit mark (right) in which the peep tails left impressions with movement up and out of the excavation.

Peeps are rarely sighted outside of small, cellophane-wrapped boxes in urban shopping centers. Nevertheless, one spring I was lucky enough to see a gaggle of them (five, of course), exuberantly unbound. on a beach of Sapelo Island, Georgia. Thus I was able to observe them making trails, landing traces, resting traces, and actively burrow just above the intertidal zone, which may very well be their natural habitat.

Five peeps making a trail as conjoined unit on a Sapelo Island beach, a behavior predicted by their traces. Who says ichnology isn’t a real science?

Peep landing marks from a short aerial excursion, with the peep presence a short distance away also supporting the interpretation of their bouncing forward after landing.

Peeps exiting a shallow burrow that was also a resting trace, a blend of behaviors often implied by traces.

Peeps initiating a deeper burrowing strategy, perhaps as a form of predation avoidance. Note how the trail becomes shortened, straight, and produces a large pile of sand in front of the direction of movement.

Never-before-seen evidence of how these legless peeps burrow! They use a combination of minute lateral undulations and forward movement directed downward at a shallow angle. As a result, the trail entering the burrow becomes covered by sand ridges produced by the subsequent behavior.

Success! These peeps have managed to bury themselves, leaving only a small portion of their heads exposed, with all five watching warily for predators,

Peeps have been the subject of intensive research, but much of this work, however valuable, has been laboratory based and highly experimental. Thus the data I’ve presented here on their traces should greatly expand our understanding of their behavior in the context of natural settings. Further insights on the biology of peeps are currently murky, but their traces hold promise of fitting them into a taxonomic category more precise than “looks like little chicks.”

Although trace fossils of peep trails, landing traces, resting traces, and burrows have not yet been discovered, I propose these should have the following ichnogenus and ichnospecies names: Peepichnus quinquecalles (= “Peep trace of five trails”). However, I anticipate some of my ichnological colleagues will want to split the ichnotaxonomy of peep traces on the basis of whether they were moving horizontally versus vertically (the peeps, not my colleagues) and other such nuances. Personally, I think they just need to relax, stop coming up with so many silly, unpronounceable names, and just enjoy the sweetness of these little tracemakers of the Georgia coast.

Life Traces of the Georgia Coast

Unseen lives of the Georgia barrier islands

Tag Archives: outdoor science