Vestiges of Home

I first became a scientist in my backyard. This path to life-long inquiry began when I was four years old, as soon as my family moved to a larger house, and one with a larger yard. This small, outdoor patch of land with a few large trees, bushes, and grass soon became my field area, laboratory, classroom, and all-purpose place for conducting experiments in nature. Even better, my proclivity for observing this world outside of myself was encouraged – or at least tolerated – by my mother and father.

At the time, I had no idea just how important of a role this backyard and parental support would play in my scientific career. Yet now I look back on it with a mix of gratitude and wistfulness, especially as both of my parents have departed this earth I have studied for most of my life.

Backyard-Home-IndianaHere’s where I first learned science by going into the field. Back in the day, people – including my parents – called it a “backyard.” (Photograph by Anthony Martin.)

Indiana was an odd place for a natural scientist to develop in the 1960s. I recall how kids in public schools there and then were encouraged to study and pursue careers in science. However, this was mostly because of the “space race,” in which the U.S. was competing against the U.S.S.R. to see who could first land on the moon. I loved space, staring at the moon, planets, and stars, and I watched Star Trek (the original series, of course), dreaming of some day traveling in space. Science fiction stories became an outlet for me as well. Weekly trips to the public library meant checking out books by Arthur C. Clarke, Ray Bradbury, and other sci-fi writers who expanded my perspectives and kick-started my imagination with worlds far different from those I could experience in the Midwest.

Yet science fiction wasn’t the only subject that put me on a first-name basis with librarians as I checked out stacks of books. There were two other topics that supplemented my learning, namely dinosaurs and insects. Although the study of dinosaurs had not yet gone through its major scientific revolution of the 1970s, these animals still loomed large in my and other children’s inner worlds. “Tyrannosaurus rex! Stegosaurus! Brontosaurus!” we kids would shout gleefully at one another, or at bemused adults. Books with artistic recreations of dinosaurs and the occasional movie starring dinosaurian protagonists – such as The Beast from 20,000 Fathoms, The Valley of Gwangi – fed our fancy, too.

Charles-Knight-PaintingPhoto of the original mural of Charles Knight’s ‘Triceratops and Tyrannosaurus‘ (1927), which is in the Field Museum of Natural History in Chicago, Illinois. While growing up, I saw this image many times in books, and it inspired both my artistic and scientific leanings. (Photograph by Anthony Martin.)

Still, no matter how hard I imagined, I could not see a tyrannosaur in my backyard, let alone watch it stalk and devour its prey. In contrast, insects and other animals with jointed legs delivered Tennyson’s “nature red in tooth and claw,” and much more. For about nine months of any given year during my childhood, starting in the spring, I could step out the back door of my house and watch ants, bees, wasps, butterflies, moths, spiders, and praying mantises. Plant-insect interactions in particular – such as pollination, herbivory, and wound responses in plants – drew me in, teaching me those ecological principles long before I ever heard the words “pollination,” “herbivory,” and “wound response.”

Roses-Pollination-Bee-HomeRoses blooming in the front yard of my Indiana home in August 2014, attracting a pollen-gathering carpenter bee (probably Xylocopa virginica). Female carpenter bees leave exquisitely crafted traces in wood, boring into them to make brooding cells, which they provision with pollen balls. The rose bush was originally planted by my father in the late 1970s. (Photograph by Anthony Martin.)

Leave-Insect-Feeding-TracesInsect damage on the leaf of an apple tree in the backyard of my Indiana home in August 2014. The leaf mine (left) was probably caused by a different insect from the one that made the incision along the leaf margin just to its right. Notice the brown discoloration in the leaf, a trace of its response to these injuries and its healing. My father planted this apple tree, but I’m not sure when: maybe also in the late 1970s. (Photograph by Anthony Martin.)

Predation fascinated me, probably because death was such an inappropriate topic for children to discuss with their parents. This wasn’t the artificial, acted-out stuff of TV and movies, but was in your face, or rather, in front of your face. With mild shame now (and apologies to my Buddhist friends), I remember going into my backyard, picking up ants, and throwing them into wolf spiders’ ground webs. It was a repeatable experiment in which I could observe spider response-times to tactile stimuli, and it was real.

My backyard is also where I learned to sit still and wait. As soon as I spotted a praying mantis, it was only a matter of time before that magnificent, big-eyed head swiveled to lock onto a target, moved delicately toward it, and sprang its barbed arms forward to snatch and hold its squirming dinner, which it devoured alive. Who the hell needed TV, with sharks, lions, and polar bears, when you had this, and for free?

Ah, there’s that word, “free.” This connects to the main reason why my science leaned more toward field observations and less to indoor labs, a legacy that stuck. You see, my family was poor. I didn’t know this until other kids at school made fun of my shoes, which had holes in their soles, or my pants, which were too outgrown or ragged, or my haircuts, which looked odd because my mother cut it, and badly, but with good intentions, because haircuts done by barbers were just too expensive. Compounding this (and not coincidentally), my mother and father never went to college, and my parents struggled to maintain their traditional roles, for which they were ill suited to succeed.

My father was a veteran of World-War II, and late in his shortened life was diagnosed with PTSD (post-traumatic stress syndrome), which in the 1970s was labeled “shell shock.” This condition meshed all too well with his alcoholism, meaning he had trouble keeping down a job for more than a few years. His last paycheck came from working as a night-shift janitor at a Columbia Records distribution center in Terre Haute. This job ended once he began suffering from a series of serious illnesses that put him in and out of hospitals for the last 15 years of his life. Only 59 years old, he died in the summer of 1985, just a few months before I left for Ph.D. study at the University of Georgia.

Dad-Then-LaterMy father at six months old (in 1927) and near the end of his life (circa 1982). His mother was still alive when the photo at the left was taken, but he never got to know her; she died when he was only two years old. During his last ten years of life, he developed a fondness for roses, cultivating them in our yard and bringing beauty to our home every year.

My parents were also Catholic, which in their time meant the only birth control they used was prayer. As a result, we had a big family, and I grew up with four brothers and one sister. But we were also reminded of unseen siblings, the ones who might have been. My mother was pregnant 13 times, with six successful births, but also six miscarriages and one stillbirth, meaning she bore more deaths than lives. Much later, I realized how this must have placed a profound emotional burden on her, even though she almost never mentioned it.

Judging from my mother’s affection for books and reading, I think she wanted to be an intellectual of sorts, perhaps even a scientist, or at least she wanted to learn and debate ideas with other people. This, however, was not possible when cleaning, cooking, shopping, paying bills, and otherwise taking care of six kids, all while constantly pregnant until she had her last child in 1962. Add to those demands a chain-smoking, alcohol-fueled, and narrow-minded husband who helped with none of those household tasks, followed by her being his in-house nurse and servant during the last 15 years of his life, and she didn’t stand a chance of reaching those ideals.

Dad-Back-From-War-with-MomHappier times for my parents, soon after my father came home after his service in the U.S. Army during World War II, where he fought in the Pacific. It would be his only trip abroad, but it scarred him for the rest of his life, which affected everyone around him. My mother never traveled outside of the U.S. and stayed in the Midwest for nearly all of her life.

Given such a family history, I experienced class differences and situations in college and graduate school that perplexed and occasionally stung. Even now, despite having taught at an elite private university for nearly 25 years, I still wrestle with imposter syndrome, and with how much my background sets me apart from others in my rarified academic world.

For instance, many of my academic colleagues are second-generation academics, or otherwise come from more socially elevated or well-to-do (or at least middle-class) families, where they never had to worry about paying the bills in time and making it through the month. Moreover, most of the students I’ve taught over the years have almost never experienced such economic anxieties, either. Behind all of the science I do and teach, and all of my achievements, I still hold onto a nagging, debilitating fear of scarcity, and a secret shame of how my family was on welfare and used food stamps to buy groceries. The taste of government cheese still lingers.

In the 1960s, education seemed like a way to escape from the cycle of poverty, and that was the message I constantly received from my mother and father. Sadly, that message sometimes translated as, “Don’t be failures like us.” Later in life, I turned that little frown upside down when I traveled, met wonderful people, and made scientific discoveries, many of which happened whenever I did field work in places far away from that backyard in Indiana.

Victoria-Coast-CretaceousIn grade school music class, I used to get in trouble for singing the chorus of Waltzing Matilda a bit too boisterously, which happened in between reading books about dinosaurs and insects. About 40 years later, I was walking along the coast of Victoria, Australia, looking for dinosaur tracks and insect trace fossils in the Cretaceous rocks there. Funny how that happens sometimes. (Photo by Ruth Schowalter.)

But here’s the thing about that whole “education helps people to escape from poverty” trope, one seemingly affirmed by my little personal story. This was much easier to do in the 1960s than today. The gap between the poor and rich in the U.S. today is the worst it’s been since the 1920s, with no sign of abating. People who wants to preach their faith-based mantra of “People just need to work harder to succeed” conveniently overlook that Horatio Alger was a second-generation Harvard man and Ayn Rand took government assistance. Also, an increased emphasis on student loans to pay for exploding tuition rates during the past 30 years has meant young, aspiring scientists may be starting their careers with crippling debt.

But here’s another thing: I was damned lucky because of my parents. Not despite them, but because of them. That’s what I say – and with considerable ferocity – every time someone tries to tell me (in a well-meaning way) how much my life reflects “the American dream.” For one thing, I grew up at a time when white boys were far more encouraged to go into science than African-American boys, or all girls. This accident of being born male, and in a family belonging to the dominant ethnic group of my culture, meant I benefited from the privilege of my gender and race, even as my socioeconomic background held me back.

Flagpole-ClimbingThat’s me, climbing a flagpole just outside my house when I was about seven years old, circa 1967. The rest of my family was standing below watching, cheering me on, and documenting the event. Little did I know at the time that other kids were told they couldn’t climb flagpoles, let alone make it to the top. Yes, that’s a metaphor. (P.S. The flagpole’s gone now.)

I also had lots of help along the way, such as financial aid and scholarships in college, and teaching assistantships in graduate school. This meant I didn’t have to take out student loans. Sure, I had less than $100 to my name the first month I began the teaching job I still hold (so far), but at least I began that job debt-free. Many of today’s aspiring scientists don’t have this luxury, and entrenched inequities related to gender and ethnicity continue to discourage careers in science for most Americans. Also, achieving a college degree today is nine times more likely if you come from an upper-income family than a poor one. It was never easy for poor people to become successful scientists, but it’s far, far tougher today. I was lucky.

Perhaps most importantly, though, I had parents who let me play outside and supported my learning science, however weird I must have seemed to them. I mean, staying out in the backyard for hours, flinging ants in spider webs, and watching praying mantises kill other insects? That was pretty strange, even in the 1960s. I even climbed trees in our backyard. I suspect that many of today’s “helicopter parents” would have forbidden a scrawny runt like me from going outside, let alone get my face close to spiders and insects, and handle unknown plants. Climbing trees probably would have involved first donning a series of ropes, carabiners, harnesses, padding, and a helmet, all while being supervised by a team of tree-climbing experts. Instead, like any arboreal primate should, I climbed those trees by myself, occasionally fell out of them, then got back up and climbed again. I was lucky.

Climbing-Pine-TreeMy favorite climbing tree in my backyard, which I started scaling when I was about six years old, so it must be more than 70 years old now. It was great fun to see how far I could get up into it and explore, and I found much peace just sitting in its crooks, watching the world below. Notice in the close-up (right) all of the scars on the trunk, marking the sites of the low-hanging branches, which fell off the tree a long time ago. (Yes, that’s another metaphor.)

My parents also regularly took me to our modest public library, where I checked out many books, which I read, and sometimes re-read. After my grade-school teachers alerted them that I was showing talent as an artist, my parents also spent some of their meager cash to buy me crayons, pencils, paper, acrylic paints, oil paints, and canvases as birthday and Christmas presents. So I drew and painted, and nature was my inspiration for such creations. I still can draw well – and sometimes teach drawing to my students – because of what my parents did for me. I was lucky.

Insects-Then-NowOne of my earliest attempts at scientific illustration (left), coupled with one of my more recent efforts (right). The one on the left – clearly intended as a multi-part figure – shows some of the insects I observed in my backyard, as well as some of the ecological interactions they had as pollinators, predators, and prey. The one on the right is from Figure 5.4a in Life Traces of the Georgia Coast (2013, Indiana University Press, p. 192), and is the subsurface form of a nest made by Florida harvester-ants (Pogonomyrmex badius); scale bar = 25 cm (10 in).

As I do field work today, I silently thank my father for taking me on hunting and fishing trips, effectively planting the seeds for my present-day comfort with forests, streams, lakes, and other outdoor environments. On those hunting trips, I learned what little my father knew then about tracking animals, a skill that I honed later in life, and now one of my passions. On fishing trips, I watched the behavior and ecology of freshwater crayfish, which abounded in the streams of southern Indiana. I had no clue that more than 40 years later I would reconnect with that childhood interest in crayfish by discovering the oldest fossil crayfish in Australia. I also did a different kind of fishing by studying and interpreting fish trace fossils, such as a trail left by a bottom-feeding fish about 50 million years ago in Wyoming. Then I combined my childhood love of insects and dinosaurs by writing and publishing a paper about Cretaceous insect cocoons near dinosaur nests in Montana. I didn’t see an ocean until I was 20 years old, but last year published a 700-page book, Life Traces of the Georgia Coast, which I also illustrated myself. None of those things would have happened without my parents’ help early in my life. I was lucky.

My father and mother did what they could with what life dealt them, and my mother in particular. She was born in northern Illinois and lived there through the Great Depression during her childhood. While there, she met her high-school sweetheart, who some day would be the father of her six children. He went off to fight in a world war, she waited for him to return, and they married soon afterwards. They headed south to Terre Haute, and lived in one house, then another. The latter was her home for 50 years.

Mom-Honeymoon-OutcropMy mother on her honeymoon at Turkey Run State Park in southern Indiana, 1947. While looking through a photo album in 2012, I was delighted to see this photo, showing her when she was fully in love with my father, but also enjoying what must have been a glorious waterfall. Best of all for me, though, it has an outcrop of Late Carboniferous (Pennsylvanian) Period deltaic sandstones in the background.

My mother outlived my father by nearly 30 years and got to see how her love of books, reading, and encouragement of my learning came back home to her. In 2001 and 2006, it was with much pride I mailed her each edition of a textbook I wrote and published (Introduction to the Study of Dinosaurs). In the preface to Life Traces of the Georgia Coast, I pointedly thanked her and my father for cultivating a childhood life filled with books, art, and the outdoors.

Mom-Then-LaterThe first and last photographs of my mother, when she was three years old (about 1929) and just last month, the latter photo taken by my brother Pat.

My mother died three weeks ago. The first stroke was toward the end of December 2013, and its treatment necessitated her going to a hospital, and then to assisted care. For the next eight months, she had a picture window that looked out onto a courtyard, where she watched the blooms, butterflies, and birds of what would be her last Indiana spring and summer. On August 26, she had a second and more deadly stroke, putting her in a coma that took away all of her speech, thoughts, and memories. After receiving emergency care in Terre Haute, she was evacuated by helicopter to an intensive-care unit in Indianapolis that same night. Six days later, she exhaled for the last time, less than a week shy of her 88th birthday.

Decatur-Book-Festival-Dedication-MomMe giving a talk about my most recent book, Dinosaurs Without Bones (2014) at the Decatur Book Festival last month. At the end of my talk, I dedicated it to my mother. Almost no one in the audience knew she was in a coma at the time, and none of us knew she would die three days later. (Photo by Ruth Schowalter.)

Just before this second stroke, I flew up to Indiana to see her, and we spent some time with our extended family, but also some quiet moments talking together, just mother and son. During this visit, I told her how much I appreciated everything she had done for me. We got to say goodbye to one another. We were lucky.

Today I am a trace of my mother’s and father’s love and care, and a trace of my home and backyard in Terre Haute, Indiana. Given more luck, I’ll be around for a while longer, leaving more traces of my own, and in many more places. Thank you, Dad. Thank you, Mom. You did good.

Mom-Me-Then-LaterFirst and last photos of my mother with me, separated by more than 50 years. As you can see from both pictures, my disposition hasn’t changed much. And thanks to Mom, it probably won’t.

High Plains Anteater

Every time I travel away from home, I make a point of looking at the ground. The main reason for this seemingly odd behavior is to make sure I detect traces of whoever else might be living in my temporary neighborhood. This ichnological practice came in handy last month while I was doing field work in the high plains of central Montana. Located just east of the front range of the Rocky Mountains, this area – which happens to have some lovely Late Cretaceous trace fossils – is also prime real estate for grizzly bears.

Grizzly-Bear-Scat-Montana-Ants-1Had we found this in the woods, it would have answered just one specific question. But because it was in the high plains of Montana, it generated a lot more questions than answers. (Photograph by Anthony Martin, taken in central Montana.)

Grizzly bears (Ursus arctos) are the largest land carnivores in North America. The earliest written records describing grizzly bears came from Meriwether Lewis and William Clark, who traipsed through this part of Montana with their expedition in the early 19th century. After several encounters, they soon verified that this species was much tougher than they had presupposed, often taking more than ten shots from then-modern rifles to kill. To make matters worse, it had a low tolerance for upright bipeds traipsing, skipping, sashaying, or dosey-doeing in its territory. Moreover, these bears possessed the means to enforce their you-no-go-here zones. There’s something about weighing 300+ kg (700+ lbs), having powerful limbs ending in huge claws, big teeth, an ability to run more than 50 kph (30+ mph), and an aggressive attitude that persuasively argued for people to avoid them whenever possible.

Bear-Treeing-PersonLewis and Clark thought they were badasses because they carried boom sticks, but Mr. Chocolate soon showed them why grizzlies were the Mongos of the animal kingdom: shooting them sometimes got them mad. (Image is originally from Sargent Patrick Gass’s journal and borrowed from Frances Hunter’s American Heroes Blog, co-written by Mary and Liz Clare.)

So although the area where I did field work in Montana is world famous for its dinosaur nests and other fossil evidence, modern grizzly-bear traces there also mean I associate this place with these animals. For instance, I’ll never forget my first morning there in 2000, when – while walking to an outcrop I’d be studying by myself for the next six days – I encountered fresh grizzly tracks in one of the arroyos. These traces readily explained why I heard a pack of coyotes making a racket the night before, while also invoking mild anxiety in this petite paleontologist once I realized the surrounding environment lacked any trees or other means of escaping an angry grizzly.

Grizzly-Bear-Tracks-MontanaLeft rear-foot track of an adult grizzly bear, left in the muddy sand of an arroyo next to a Cretaceous outcrop where I did field work in 2000.  Notice the length of its claws, which left marks well in front of its toes. Photo was taken about four days after I had seen them freshly made my first day in this area of Montana. (Photograph by Anthony Martin.)

This time, with 14 more years of tracking experience behind me, I felt a little more confident about detecting grizzly-bear tracks and other sign, and looked forward to seeing these traces, but not their tracemakers. Thus I was pleased when my field companions and I found several-weeks-old evidence of a grizzly during my first morning there. Yet these traces were not tracks. Instead, they consisted of scat bearing (sorry) some never-before-seen items (for me, anyway), accompanied by nearby feeding signs that directly connected to another trace made by another animal.

So let’s first talk feces. Based on its size alone, we quickly determined that this deposit was from a grizzly bear, as the two pieces collectively were about 15 cm (6 in) long and about 5 cm (2 in) wide. Nearby coyote scat nearby gave some perspective: although 20 cm (8 in) long, it was only 2 cm (0.8 in) wide, indicating a much smaller anal diameter. However, that wasn’t the largest grizzly scat I’d ever seen, which made us think that maybe it was from a young bear.

But was really puzzled us was the contents of the scat: it was full of ants and grass stems. Despite none of us being entomologists, let alone myrmecologists, we recognized the red-and-black ant parts in the scat were from an ant common there in the high plains, and probably some species of Formica. Colonies of this ant built nests with prominent domes at the ground surface, which are composed of a mixture of soil and grass stems. Hmm, ants and grass stems: what could it mean?

Grizzly-Bear-Scat-Montana-Ants-2See all of those orange and black bits in this scat? Those are ant parts that passed through the digestive tract of a grizzly bear. Notice these pieces are accompanied by lots of plant fibers, which must have provided some healthy roughage. (Photograph by Anthony Martin, taken in central Montana.)

OK, you already got it: this scat was evidence of a grizzly bear that ate ants. But the grass also showed that this grizzly ingested a lot of plant debris along with these yummy insects. This implied that it must have been chowing down on the top of an ant nest, scooping up insects and grass stems indiscriminately, like it was dining on an ant salad. Furthermore, knowing how ants tend to defend attacks on their nests, they probably swarmed upward in great numbers and straight into this grizzly bear’s mouth, unwittingly aiding its efforts. (Incidentally, an insectivorous member of our field crew had been tasting these ants just minutes before we found the scat and independently confirmed their delectable qualities.)

Montana-Ant-Nest-2Ant-nest mound in the field area composed mostly of grass stems, and probably made by a species of Formica. Scale is a size 8 1/2 (men’s) boot. (Photograph by Anthony Martin.)

Montana-Mound-Nest-Ants-CloseupClose-up of the ants in the colony moving in and out of a nest entrance, in between all of the grass stems. Also, check out those black abdomens and reddish-orange thoraxes and heads, which we now know don’t change color much after spending time inside a grizzly bear. (Photograph by Anthony Martin, taken in central Montana.)

So how did we know that the grizzly was “scooping” (using its paws) instead of simply mashing its face into the nest like it was competing in an ant-eating contest at a grizzly-bear fair? Ah, that was the other trace evidence. Only a couple of meters away from the scat were two big pits. These pits showed exactly where the ant-eating grizzly had used its big-clawed paws to rip into a couple of nests. While taking into consideration the needed residence time of ants in a grizzly gut, we figured this bear had already raided a nest somewhere else and pooped here, or it came back to this place for seconds the next day. Either way, it left a little calling card for us bipeds and any other mammals in the area, warning us to stay away from its ant stash.

Grizzly-Bear-Ant-Predation-PitsEver wonder what a grizzly-bear-ant-eating pit looks like? Wonder no more, here’s two of them. The one on the left was about a meter (3.3 ft) across, whereas the one on the right was closer to 1.5 m (5 ft) wide. (Photograph by Anthony Martin.)

What was very gratifying about these traces is how they reflected the same sort of insectivorous bear behaviors I had discerned in black-bear traces in forests of Wyoming and Idaho. The big difference, though, was in the types of insects and substrates. Insect-eating bears in forests rip open rotten logs for their fodder, which mostly would hold wood-eating beetle grubs; this behavior leaves huge gouges and scatters wood chips around the feeding site. Without trees, the same behavior means digging into the soil, and after different insects, such as  moths and ants, and the traces will be large pits like the ones we saw.

So how would traces like these look in the fossil record? Better yet, how would our knowledge of these grizzly-bear traces help us to test whether any dinosaurs did similar behaviors, such as tearing into Mesozoic ant or termite nests and feasting on these little protein-rich treats?

Well, you’re lucky that I’m the person asking such rhetorical questions, because I just happened to have talked about about this in my most recent book, Dinosaurs Without Bones. Based on their anatomies, dinosaurs accused of ant- or termite-eating behaviors include a few unusual theropods, such as alvarezasaurs and therizinosaurs. Very simply, dinosaur trace fossils of insectivory would be analogous to what we saw with these grizzly-bear traces in Montana. Lacking dinosaur skeletons with insect parts in its gut region, trace fossils might include coprolites containing abundant ant parts, accompanied by sediments or plant debris from their nests. Even better would be a fossil ant or termite nest with visible damage matching the claws or other body parts of these suspected dinosaurs.

Have paleontologists ever found such two-for-one ichnological specials? Not yet, but given an awareness of modern insect-eating animals and the traces – some of which are next to Mesozoic rocks – I have every confidence that we’ll discover find them some day.

Burrowing Wasps and Baby Dinosaurs

Anyone who knows a little bit about dinosaurs knows that some of them made nests, took care of their young, and that their parenting skills must have been more like birds, rather than most reptiles. If pressed, most dino-enthusiasts can further say this concept is exemplified by two dinosaurs, the large ornithopod Maiasaura and the small theropod Troodon, both of which lived at the same time and place, 75 million years ago and in what we now called Montana.

But what animals lived beneath the nests and feet of those dinosaur parents and their babies? What behaviors did these animals express 75 million years ago? Would the behaviors of these animals have resembled those of ones living today, or did they reflected evolutionary dead-ends? And did these animals also take care of their young?

Wasp-Digging-Burrow-Tybee copyWhoa, check out this female Carolina sand wasp (Stictia carolina), energetically digging an inclined burrow into a Georgia coast dune! Why is she digging a burrow? To make a brooding chamber for her babies (larvae), who will hatch from their eggs and chow down on paralyzed prey stuffed into that chamber by their thoughtful mama. Gee, I wonder if any wasps did this in the geologic past? (Photograph by Anthony Martin, taken on Tybee Island.)

Cretaceous-Wasp-Burrow-Pupal-ChamberWhy, yes, they did. That’s a fossil cocoon connected to an inclined burrow, reflecting a behavior much like that of modern sand wasps, but preserved in the Late Cretaceous Two Medicine Formation of central Montana. (Photograph by Anthony Martin.)

The answers to these questions are, in order: insects (wasps and beetles; most likely), burrowing and reproduction; they behaved very much like modern insects, and they likely did take care of their young by making brooding chambers and leaving food for their offspring. In my experience, these revelations surprise many people, who may not be aware of how many of the insects we live with today are descended from insects lineages that shared the same ecosystems with dinosaurs throughout the 165-million-year history of the latter animals.

This summer, for me to learn more about life underground way back then, I had to go to the same site in central Montana where our understanding of dinosaur parenting became better defined, but also where I first learned how insect parenting related to dinosaur parenting. Where I am now is the same general location where the first known dinosaurs nests in North America were found in the late 1970s by Jack Horner and his friend Bob Makela (mentioned in my previous blog post).

One of the most productive and interesting of these nest sites, which are all in the Late Cretaceous Two Medicine Formation, was informally dubbed “Egg Mountain.” The “Egg” part of the moniker is easy to understand, but the “Mountain” part is more of an exaggeration, as it’s an isolated and modest hill on the high-plains landscape of central Montana. Anyway, I’m working there now, along with a dedicated crew of rubble pickers being led by the ever-intrepid Dr. David Varricchio.

Egg-Mountain-Digging-2A snapshot of science in process at Egg Mountain in central Montana. Dr. David Varricchio (center, with jackhammer) has been leading an NSF-sponsored study of the fossils at this site, with the hope of understanding more about nesting dinosaurs and the animals that lived around them. Rubble pickers for scale. (Photograph by Anthony Martin.)

So why would an ichnologist like me care about a site that is famous for its mere body fossils, consisting of many dinosaur eggs, eggshells, and bones? I’ll start with three words: dinosaur nest structure. This is where the first known dinosaur nest structure – which is a trace fossil – was recognized. The structure was a rimmed depression about the size of a kiddie pool, but a little more shallow. In the center of this depression was a clutch of eggs belonging to the small theropod Troodon. The width of the nest was perfect for accommodating an adult Troodon, which probably sat above the egg clutch to protect and incubate it.

Troodon-Nest-StructureHere’s the first known dinosaur nest structure, as it looked soon after its discovery in the mid-1990s. The rim is composed of limestone, but originally was soil compacted and shaped by either one or both Troodon parents. The white part is plaster of Paris covering the egg clutch, which was aligned with the dead center (pun intended) of the structure. Tape measure shows 1 m (3.3 ft). Photograph was probably taken by David Varricchio, and is from Varricchio et al. (1999), Journal of Vertebrate Paleontology, v. 19, p. 91-100.

Troodon-Nest-with-Eggs-MartinMy artistic recreation of this same rimmed Troodon nest structure with its egg clutch in the middle. The inner part of the structure – inside the rim – is about a meter wide. (Artwork by Anthony Martin, from Dinosaurs Without Bones (2014), which you should buy so I can better afford to do more research like this and blog about it for you.)

What’s even better about this find – ichnologically speaking – is how the parent dinosaurs must have moved the eggs after the mother laid them, and then partially buried them upright in soil. These eggs are elongate, which means they would have reclined if laid by a mother Troodon. Instead, they were nearly vertical, which means either the mother or father dinosaur manipulated these eggs after they emerged from the mother dinosaur. Thus this orientation is also a trace fossil of parental dinosaurs that were greatly increasing the chances their future offspring would stay alive.

Troodon-Egg-ClutchBottom view of the Troodon egg clutch from that nest structure, with these elongate eggs in nearly vertical positions, and aligned along a central axis. These arrangements of the eggs are trace fossils, too. Want to see this clutch for yourself? It’s is on display in the Museum of the Rockies in Bozeman, Montana. (Photograph by Anthony Martin.)

Now let’s leave dinosaurs for a moment and talk about something that really matters, like insect trace fossils. What is well known by those who have worked at Egg Mountain is that the dinosaurs there were not alone. Just below the dinosaurs’ nests, egg clutches, and feet were insects, and lots of them, shown by numerous cocoons. In a few places near Egg Mountain, these exquisitely preserved cocoons – most with their spiraled weave patterns still visible – are so common, you can close your eyes and scoop up a handful of them.

Fossil-Cocoons-MontanaFossil insect cocoons from the Two Medicine Formation and a locality near Egg Mountain. The cocoons on the left and right are ichnological two-for-one specials: the left one has a partial burrow attached to it, and the right one has an emergence trace (top) from where the adult insect said goodbye to its cocoon 75 million years ago. (Photograph by Anthony Martin.)

In an article I coauthored with David Varricchio in 2011, we concluded that most of these insect cocoons were likely from burrowing wasps, and the rest may have been from beetles. The trace fossils reflect a unexpectedly modern behavior in these Cretaceous wasps, which dug inclined tunnels that led down to enlarged brooding chambers. These insects laid eggs in the chambers and stocked them with provisions, which may have been paralyzed prey, such as other insects or spiders. Later, larvae hatched in the chambers, ate whatever Mother Wasp left for them, made cocoons around themselves once they decided to stop being so larval, pupated, burst out of their cocoons when they became adults, and emerged on the surface.

Stictia-BurrowMy simple depiction of a burrow and pupal chamber made by the solitary Carolina sand wasp (Stictia carolina). These traces consist of inclined tunnels that end in enlarged chambers, the latter of which accommodate eggs, food, and eventually larvae and cocoons. Scale = 10 cm (4 in). (Illustration by Anthony Martin, which is in Life Traces of the Georgia Coast (2013), which you should buy so I can better afford to do more research like this and blog about it for you.

Cretaceous-Wasp-Burrow-Pupal-Chamber-2Close-up of the burrow end – filled with sediment, but now rock – leading to a cocoon, still preserved in its pupal chamber in the Two Medicine Formation, from about 75 million years ago. Compare this to my illustration of a typical modern sand-wasp burrow, especially the end part of it. Notice the resemblance? (Photograph by Anthony Martin.)

However, most of the fossil cocoons in the Two Medicine Formation did not make it past the pupal stage. How do we know this? Because some of these outcrops have thousands of cocoons that are perfectly preserved as beautiful ellipsoids, with no sign that an adult insect emerged from them. One of the axioms of paleontology is that each animal’s tragedy of the past can some day fulfill a paleontologist’s dreams. Thus these thousands of dead Cretaceous wasps are providing me with much joy this summer, as I study these trace fossils for more clues about their lives and how they related to the ecosystems they shared with adult and baby dinosaurs.

Martin-Fossil-Cocoons-MontanaA picture of one happy ichnologist, who is giving thanks for all of those insects that died and had their burrows and cocoons fossilized in the Two Medicine Formation for him to study. Thanks, insects! Thanks, geology! (Photograph taken by Ruth Schowalter in central Montana.)

But here’s what really cool about Egg Mountain: it has both dinosaur nests and insect nests, implying that wherever these insects nested, so did the dinosaurs. As a result, their co-occurrence gives us a glimpse of the ecology of those places at that time, a window into the past landscapes in which they lived and bred. This makes sense when you imagine how both these dinosaurs and insects wanted to keep their eggs out of water, so they placed them in high-and-dry areas, such as well-drained soils well above the water table. So as we gather more information from this site, we get ever-better insights in the cycles of life for both Cretaceous insects and the dinosaurs that happened to live in their world.

Tracing the Two Medicine

Field scientists have to get into the field. If they don’t, they get cranky, narrow-minded, and – worse of all – feel like frauds. What’s the cure for this malady? Getting into the field.

Tony-in-the-FieldSee that smile? That’s a field scientist, who is out standing in his field. (Photograph by Paul Germano.)

This is the first summer since 2008 in which I did not have to edit or write a book. From 2008 to 2012, I was writing and editing Life Traces of the Georgia Coast (2013, 692 pages), and from 2012-2013, my literary efforts were devoted to Dinosaurs Without Bones (2014, 460 pages) So with these two books behind me and none in the making now, along with three merciful months off from my “day job” of being a college professor, I had few excuses for not getting outside to see some rocks and fossils this summer.

So it was with much joy when my long-time friend and fellow paleontologist David (Dave) Varricchio asked me earlier this year if I’d be interested in coming out to Montana to do some field work with him this summer. Even better, I’d get to do paleontological field work with him in the Late Cretaceous Two Medicine Formation (~75 million years old) at “Egg Mountain,” a paleontologically classic area near Choteau, Montana. I said yes, have been here for a week now, and it’s been glorious.

Egg-Mountain-Digging-2 To look for traces, sometimes you have make your own traces. Here’s this summer’s Montana State University field crew excavating at Egg Mountain, where they’re looking for dinosaur bones and eggs, while also cataloging trace fossils like insect cocoons and burrows. If you’re looking for Dr. Varricchio, he’s the one in the middle with the jackhammer. (Photograph by Anthony Martin.)

The main reason why the field site is called “Egg Mountain” is because it and other places in the area are where the first known dinosaur nests in North America were discovered by Jack Horner and Bob Makela in the late 1970s and early 1980s. They further uncovered evidence that at least one dinosaur here – the large hadrosaur Maiasaura peeblesorum – had extended parental care, taking care of its young in their nests well after hatching.

Later in the 1990s, Dave and his colleagues showed that the small theropod Troodon formosus made rimmed ground nests and arranged it eggs carefully in these nests. This combination of body fossils (bones and eggs) and trace fossils (nests and egg arranging) changed many of our views of dinosaurs, rendering their behaviors much less like reptiles and more like birds.

Maiasaura-Nesting-Site Sometimes I hear paleontology referred to as a “historical science,” but it also has its own human history. This marker and several others in the field area mark where some of that history was made, with the discovery of the first known dinosaur nests in North America. (Photograph by Anthony Martin.)

Two-Medicine-Formation-OutcropI love waking up to the Two Medicine Formation in the morning. And there’s no shortage of trace fossils to discover in it with each waking day. (Photograph by Anthony Martin.)

Hadrosaur-Track-Two-MedicineA natural sandstone cast of an adult hadrosaur, weathered out of the surrounding softer mudstone that – in the absence of bones – serves as a visual reminder of who lived in this area. (Photograph by Anthony Martin.)

I had been to this site three times before – 2000, 2008, 2009 – but each of those were short visits, the longest lasting only a week. This time, I would get to stay for as long as three weeks, which allows for plenty of time to better document the invertebrate and vertebrate trace fossils here. So far, I’ve only published one paper with Dave based on previous work in the Two Medicine Formation, which was on some of the insect trace fossils near the nest sites. These trace fossils gave valuable clues about how these insects lived, and in the same ecosystems as the nesting dinosaurs, which I’ll happily cover in detail in my next blog post.

Fossil-Cocoons-MontanaInsect burrow with pupal chamber (left) and two insect cocoons, one of which has a “hatching window” where the adult insect left the cocoon. Look closely and you’ll see the original silk-weave pattern still on the cocoons, which are preserved as finely crystallized calcite. (Photograph by Anthony Martin.)

So with one week of field work done, I’m happy to report that plenty of trace fossils have revealed themselves to us, and I have every expectation that more will be found in the next two weeks. And this, boys and girls, is why I am a field scientist and paleontologist: to experience that joy of discovery that happens in the same places where the plants and animals of their ecosystems breathed and died 75 million years ago. Field work never fails to take me back in time, to when those animals behaved in ways that left their traces for us recent arrivals on this earth to appreciate with wonder.

Fun-With-Field-Work-MontanaThis is my office for the next two weeks. Not bad, huh? I could get used to this, and plan to. (Photograph taken by my camera, which was set on an automatic timer.)

(For another introduction to this field work, here’s a blog post done cooperatively with my wife Ruth, who will be joining me here at the field site in just a few days.)