Biological anthropology focuses on the earliest processes in the biological and sociocultural development of human beings as well as the biological diversity of contemporary humans. In other words, biological anthropologists study the origins, evolution, and diversity of our species. Some biological anthropologists use genetic data to explore the global distribution of human traits such as blood type or the ability to digest dairy products. Some study fossils to learn how humans have evolved and migrated. Some study our closest animal relatives, the primates, in order to understand what biological and social traits humans share with primates and explore what makes humans unique in the animal world. The Dutch primatologist Carel van Schaik spent six years observing orangutans in Sumatra, discovering that these reclusive animals are actually much more social than previously thought (2004). Moreover, van Schaik observed that orangutans use a wide variety of tools and pass down skills to their young. By studying these primates, van Schaik and other biological anthropologists gain insight into the origins of human intelligence, technology, and culture. These researchers also warn that habitat loss, illegal hunting, and the exotic pet trade threaten the survival of our fascinating primate cousins. Biological anthropologists frequently combine research among primates with evidence from the human fossil record, genetics, neuroscience, and geography to answer questions about human evolution. Sometimes their insights are startling and unexpected. Anthropologist Lynne Isbell argues that snakes have played a key role in the evolution of human biology, particularly our keen sense of sight and our ability to communicate through language (Isabell, 2009). Isbell’s “snake detection theory” posits that primates developed specialized visual perception as well as the ability to communicate what they were seeing in order to alert others to the threat of venomous snakes in their environment. She points to the near-universal fear of snakes shared by both humans and primates and has documented the prevalence of snake phobia in human myth and folklore. Isbell’s research highlights how human-animal relations are central to humanity, shaping both biology and culture. Not all biological anthropologists study primates. Many biological anthropologists study fossilized remains in order to chart the evolution of early hominins, the evolutionary ancestors of modern humans. In this field of study, anthropologists consider the emergence and migration of the various species in the hominin family tree as well as the conditions that promoted certain biological and cultural traits. Some biological anthropologists examine the genetic makeup of contemporary humans in order to learn how certain genes and traits are distributed in human populations across different environments. Others examine human genetics looking for clues about the relationships between early modern humans and other hominins, such as Neanderthals. Forensic anthropology uses the techniques of biological anthropology to solve crimes. By analyzing human remains such as decomposed bodies or skeletons, or tissue samples such as skin or hair, forensic anthropologists discern what they can about the nature of a crime and the people involved. Key questions are who died, how they died, and how long ago they died. Often, forensic anthropologists can discover the age, sex, and other distinctive features of perpetrators and victims. Looking closely at forms of bodily trauma and patterns of blood or bullets, they piece together the story of the crime. They work on investigative teams with law enforcement officers and medical experts in ballistics, toxicology, and other specialties. Forensic anthropologists often present their findings as witnesses in murder trials. Not all of these crimes are contemporary. Sometimes, forensic anthropology is used to understand historical events. Excavating the historic Jamestown colony of early English settlers in North America, archaeologist William Kelso found a human skull in the midst of food remains. Noticing strange cut marks on the skull, he called upon Douglas Owsley, a forensic anthropologist working for the Smithsonian Institution, to help him figure out what the markings meant. Owsley determined that the markings were evidence of intentional chopping to the skull with a sharp blade. He concluded that the skeleton belonged to a 14-year-old girl who had been cannibalized by other settlers after she died. This interpretation corroborates historical evidence of severe starvation in the colony during the harsh winter of 1609–1610.