"What is it like being a field paleontologist?" I am often asked this question by my students and people outside of the discipline. For many people, the image they have of fieldwork is "Indiana Jones," an intrepid archaeologist in search of treasures in exotic places and dangerous situations. The image is not completely wrong, as we are in search of treasures in oftentimes remote places and less than ideal situations. However, the treasure we seek is the knowledge embodied in the fossils we seek. Successful fieldwork requires hard work, perseverance, and a bit of luck. Much of it is monotonous, tedious, and sometimes literally back-breaking. Yet, many of us spend an inordinate amount of time writing grants to do fieldwork, even though there is a very low success rate due to the high number of applications and the limited available funding. Without funding, fieldwork and follow-up analysis would not be possible as it is an expensive endeavor — costs for flights, equipment, vehicle rentals, field supplies, field crew salaries, and permits to conduct research add up to tens of thousands of dollars for each field season. Time is also an important factor. As most of us work within the higher educational system, all field-related work is conducted outside of our teaching and service duties to our respective institutions, usually during our summer and/or winter breaks. The rough conditions and long periods of separation from family and friends do not make fieldwork seem particularly attractive. One might reasonably wonder what is the appeal, and why do field paleontologists spend so much time and effort to conduct fieldwork? For me — and I suspect for many of my colleagues — it is because I am trying to answer questions that require a more complete fossil record, because I enjoy the thrill of discovery, and ultimately, because I love it. Below is a personal account of my field experiences at Laetoli, Tanzania, a site made famous when Dr. Mary Leakey and her team discovered fossilized footprint trails of Australopithecus afarensis, the species to which the famous "Lucy" belongs (Figure 1A). The experiences that I describe are from one of many expeditions led by Dr. Terry Harrison from 1998–2005.

In the Field

It is still pitch black when the first clang and clink of pots and dishes come from the kitchen tent; the cook, Ephraim, and his assistant, Felix, are getting breakfast ready. When the darkness begins to lighten from the rising sun, I get out of my tent and pour myself a hot cup of tea and grab some toasted bread with jam at the breakfast table. We are lucky that we have a cook who can bake in these rustic field environs, as many previous years were spent eating stale and moldy bread brought in from the city weeks before. I grab a chair and turn it to face the horizon, savoring the view of the expansive grassland turning to gold with the light of the rising sun. Morning greetings are exchanged as members of the field team emerge from their tents for breakfast. Fieldwork is a highly collaborative effort and an increasingly international one, such that our team consists of paleontologists, paleobotanists, and geologists from Tanzania, the United States, United Kingdom, and South Africa. After a brief discussion about the locality we will be visiting today, I go back to my tent to get ready for the day. As I brush my teeth, I watch a herd of giraffes run across the distant horizon in that oddly graceful, seemingly slow-motion stride that is so distinctive to them. I smile at the sight, absurdly happy that I am where I am, in the middle of the African savanna.

We pile into the Land Rovers and head for Locality 15 (Figure 1B). It is the westernmost locality at Laetoli and there is a short section of fossiliferous sediments exposed there. Everyone jumps out of the Land Rover eager to get started with the survey. The team spreads out and looks for fossils (Figure 2). Each person has a specific area to survey and we will often overlap since no one person will see every fossil on the ground due to various factors, such as light conditions, search image and chance. We spread out and intently look for fossils, our backs hunched and eyes glued to the ground. Fossil hunting is generally a silent affair where people are too busy to chit-chat. It is not easy to see fossils on the ground, particularly when they are similar in coloration to the sediment surrounding them and can be easily passed over as an oddly shaped pebble or rock. All fossil specimens that are identifiable, by element and/or taxon, are collected and put into bags that are clearly marked with information on where they were recovered, such as their position in the locality and their stratigraphic placement. At Laetoli, excavation is not conducted because the fossils are spread out over the landscape rather than densely concentrated in a particular area as is sometimes the case at other hominin sites. The distribution of fossils on the landscape is determined by the particular environmental and depositional conditions present when the bones were deposited and fossilized. Fossil collecting is the bulk of our activities in the field, which means that we are walking (and sometimes crawling) for most of the day; thus, aching lower backs, legs, and feet, are not uncommon at the end of the day.

Figure 2: Survey and surface collection at Laetoli.

(A) Survey at Locality 18, author is the bent over figure on the left. (B) Survey at Locality 9S resulted in the discovery of a complete tortoise shell; photograph shows team members in the process of extricating the shell (from top to bottom: Moses Lilombero, Amandus Kweka, Charles Msuya).

© 2012 Nature Education (A) Courtesy of T. Harrison. (B) Courtesy of D. Su. All rights reserved.

As we intensely survey the ground, Terry walks ahead and disappears around the bend. Not long after, he returns and tells us to follow him. He has discovered a series of previously unexplored gullies to the north with fossils eroding from the sediments. We eagerly follow him to the exposures and, almost immediately, I find a bovid (cloven-hoofed ruminant) toe bone that is freshly eroded from the sediments. Soon after, someone finds a complete cranium of a rodent. You can feel the excitement in the air as specimen after specimen is discovered in quick succession. I see a round carbonate nodule eroding out of one of the gullies, when I pick it up and turn it around, a face stares back at me — it's a fossil squirrel skull! Amazingly, many more complete skulls of rodents and hares follow, as well as a partial skeleton of what will turn out to be a new species of bovid. It is rare that animals are preserved in such completeness in the fossil record and we spend the rest of the day happily collecting the abundant fossils, reluctant to break for lunch.

When we return to camp, after a brief tea, we begin to catalogue the fossils we collected (Figure 3). Each fossil is given a specimen number and recorded in the field catalogue along with its element and preliminary taxonomic identification, locality and stratigraphic information. This contextual information is essential to paleontology because without it we are unable to make meaningful comparisons or interpretations.

Figure 3: Cataloguing at Laetoli.

(A) Some members of the team get ready for cataloguing. Fossils are sorted and prepped (if necessary). Each fossil will have a specimen card (blue cards on the table) associated with it. Each specimen card will have information on the fossil’s specimen number, locality, stratigraphic unit, element, and taxon. The same information is also written in the field catalogue (not seen). Team members are (from left to right) Amandus Kweka, Terry Harrison, Chris Robinson. (B) Close-up of the fossils collected.

© 2012 Nature Education Courtesy of D. Su. All rights reserved.

As the sun disappears beneath the horizon, we barely even notice the various hues of red, purple, and orange filling the sky. Kerosene lamps are brought out as the sky darkens and our stomachs grumble as smells of dinner cooking waft from the kitchen. As soon as we finish cataloguing, platters of rice, spaghetti, fries, cabbage, and canned beef cooked in tomato sauce are brought out. Once a week, we might purchase some chicken or a goat for a change, but for the most part, it is essentially variations on a theme at the dinner table. The food is always good and filling, and considering the rudimentary conditions in which Ephraim works, it is always amazing what comes out of the kitchen. After dinner, we gather around the fire, relax, and discuss the day, tomorrow's plans, and whatever else comes to mind. The BBC plays in the background as someone turns on a short wave radio. There is really not much else to do after dinner at Laetoli. We have no electricity, cell phone reception, or internet connection. Soon, the excitement and physical exhaustion of the day catches up with me and I wander back to my tent to record the day in my field log with the help of my flashlight.

We were truly lucky today. Discovering a new locality where paleontologists have never been is a rare occurrence, particularly at a well-known site like Laetoli. The other end of the spectrum is a day in the field when nothing or very little is found. For example, on a previous day we decided to survey unexplored areas of sediment that are outside of the main exposures of the site. We bumped over dirt "roads" for more than two hours until we reached a point where vehicles cannot pass and hiked the rest of the way through shrubs, bushes, and tall grass, while keeping an eye on the ground for snakes. Terry had set a fast pace for what we only half jokingly called a "death march." After an hour of hiking, we emerged to see the exposures for the first time. They were magnificent badlands unlike the gentle, sloping exposures usually seen at the main Laetoli localities, and we were excited by their potential. However, at the end of the day, all we had to show for the day's work was thirst, hunger, sore feet, aching backs, and a few very weathered fossil bone fragments and some snail shells — and we still had an hour hike and two hour drive ahead of us before we could have our tea. The difference between the two days is vast, but it is all part of fieldwork, and part of the reason why fieldwork is so exciting to me — you just never know what you are going to find.

After the Field

For field paleontologists, fieldwork is just the beginning of addressing their research questions. Before detailed study is possible, fossils often have to be gently removed from the matrix in which they are found, and stabilized if they are not well preserved. This is often a delicate process that requires patience and skill. While the fossils recovered constitute the primary data, in order to derive meaning from them, they must first be described and analyzed. One of the first questions asked, after correct identification of the element, is "To what genus or species does it belong?" or, in other words, "What is it?" In order to answer this question, the morphology of the fossil specimen of interest must be described in detail and compared, both qualitatively and quantitatively, to other specimens of a known taxonomic group. For example, if a jaw belonging to a member of the felid (cat) family is recovered, it would be described, measured and compared to those of various modern and fossil genera and species of felid within similar size and morphological categories. This often involves visiting museums around the world where the comparative specimens are kept. Additional analyses are also conducted (often by different researchers) to learn about the species' behavioral patterns. This is accomplished by comparing the fossil bone to its modern relatives whose locomotor and dietary habits are known; morphology reflects function, such that animals with similar mode of locomotion will have similar morphological adaptations. For example, living arboreal monkeys have special adaptations in their forelimb for moving around in the trees; fossil monkeys with similar adaptations were likely to have been arboreal as well. Studies to better understand the context of the fossils are also undertaken; these include taphonomic and paleoenvironmental analyses, which tell us about how the fossil collection was formed (e.g., washed down via a river) and the environment in which the fossil animal lived, respectively. Because fossils are generally stored in their country of origin, primary description and measurement of the original specimens can only occur there. Sometimes, casts of the specimens are made so that further comparative analysis can be conducted elsewhere. After analyses, the results and conclusions of the studies are written-up and submitted to a journal for peer review and publication so that the information gathered can be disseminated to the field at large. The process does not end here for it is a continuous one. Fossils are generally incomplete and associated skeletons are rare. Most of the time, more complete information about the taxonomy, locomotion, diet, and paleoenvironment of the fossil animal is pieced together over time as different parts of the animal may be discovered and studied at different times. This means that any new fossil discovery has the potential to improve or fundamentally change our current understanding, and this is one of the most exciting aspects of paleontology.