Undergraduate Primate Research in Kenya
Amber Jaeger’s love for science has led her not only to pursue first-hand experience in her field of study, but also make groundbreaking discoveries—quite literally! In high school, she became interested in biology and geology, and after coming to the University of Minnesota, she discovered a fascination for osteology and human evolution—specifically, the evolution of growth and development. "I've always been interested in where we came from," says Jaeger.
Now a junior, Jaeger developed her love for bones and skeletal elements, especially skulls, in a human skeletal analysis class during her first years of college. "That’s what relaxes me: going to the lab and looking at bones," Jaeger says. Her dedication to what might seem like a peculiar interest has led her to have many outstanding experiences as she works towards her anthropology degree with a focus in biological anthropology.
Specifically, Jaeger has worked on fossil excavations in Kenya, and conducted two separate research projects with Professor Kieran McNulty. One of these resulted in an abstract which has the potential to be presented at the American Association of Physical Anthropologists (AAPA) conference this spring in New Orleans. "I've been very fortunate to have these opportunities," Jaeger says, as she realizes the importance of field work and real life application of "the methods that you hear about in class every day."
Jaeger's first research project was conducted through a department laboratory internship during which she analyzed fossil mandibles from two specimens of Limnopithecus (a primitive "ape"). Working with Dr. McNulty and one of his graduate students, Ryan Knigge, she sought to find and record changes between the two mandibles—one juvenile and one adult—to see if the implied growth trajectory could help illuminate the differentiation of monkey and ape lineages more than 20 million years ago.
Jaeger worked with casts of the 19 million-year-old fossils, learning 3D scanning and processing, digital data collection, and basic statistical analysis. Using 3D models, she was able to assess similarities and differences between the fossils and modern-day monkeys and apes. Her results were stunning: the trajectory showed that "the juvenile mandible may have been a different species entirely." This discovery is significant given the incredible difficulty in classifying juvenile specimens.
Jaeger submitted her abstract of the project to the AAPA, and will "hopefully get to present a poster" on her findings at the conference this spring, an opportunity almost unheard of for an undergraduate student.
Following this, in July of this past year, Jaeger spent almost a month in Rusinga Island, Kenya, completing three field modules as part of ongoing excavations. One module regarding excavation consisted of Jaeger digging in a 1x1 meter square, in 10 cm increments, and then in arbitrary layers according to the texture and sediment types. She dug using trowels and dental picks, and later filtered the sediment through a sieve to find small bone fragments. "I found many rodent incisors, unidentifiable bone fragments, and even a partial rodent mandible with teeth," recalls Jaeger.
During this module, the daily schedule was to dig and sieve all day. "It was very tedious work so people either loved it or hated it—I loved it," she says. And, the tedium paid off: the group found one of the most complete fossil ape skulls known from this time period.
Another module involved finding a gully containing countless numbers of fossils, forcing the team to move systematically to cover the ground as quickly as possible. After numerous fossil fragments were found, they were evaluated, and further excavations were conducted if something important was found in the area. "Fossil survey is a great way to identify areas that should be excavated," says Jaeger. "If we just excavate anywhere, we might not ever find anything."
The third module regarding geology involved hiking around the island to observe land formations. Activities included measuring stratigraphic sections, identifying and describing rocks found, and mapping paleosols: fossil soils used to recreate the environment of the past.
Jaeger is currently working on her senior thesis which is also related to the growth and development of hominins. One method for determining the age of an individuals is to look at microscopic growth increments in the teeth, "allowing a very precise way to estimate age of an individual, with each increment being created at a regular interval, similar to rings in tree trunks." Jaeger explains that by analyzing CT scans of chimpanzee skulls, ranging from babies to adults, she can correlate skull features to the teeth and brain size, calibrated by these age estimates. "The goal is to see the ontogenetic trajectory by correlating how different parts of the skull grow and develop relative to the age of the individual found from the teeth." Jaeger says.
Through her impressive endeavors in the field of biological anthropology, Jaeger has prepared for her ideal future. She plans to attend graduate school and obtain a PhD in biological anthropology. Jaeger wants to become a professor in the field and conduct research in East Africa, continuing her admiration and dedication to the field. "I love anthropology because you're always learning and constantly growing with the field," she says.