Leslie Crum Aiello (born May 26, 1946 in Pasadena, California) is an American paleoanthropologist and professor emeritus of the University College London. She has been the President of Axel Lennart Wenner-Gren donated Wenner-Gren Foundation for Anthropological Research from 2005 to 2017. In 2014 Dr. Aiello was elected to the American Philosophical Society. She is currently President of the American Association of Physical Anthropologists.
Beginning in 1964, Aiello studied anthropology at the University of California, Los Angeles, earning a bachelor's degree, and later a master's degree (completed in 1970), in Anthropology. Also while working on her BA, she spent a year (1965–66) studying abroad at the University of Göttingen. She later received her PhD from the University of London in human evolution and anatomy. Aiello remained at the University of London where she became a professor of biological anthropology starting in 1995. Also during this time, she served as the co-managing editor for the Journal of Human Evolution (1993-1999). She was also the head of the UCL Anthropology Department (1996-2002) and the UCL Graduate School (2002-2005).
Aiello is among other things a Fellow of the American Association for the Advancement of Science and the Zoological Society of London, and since 2011 a member of the German Academy of Sciences Leopoldina and since 2014, the American Philosophical Society.
She also has co-authored the textbook, "An Introduction to Human Evolutionary Anatomy” (Academic Press, 1990), which uses the fossil record to predict the ways early hominids moved, ate, and looked. She is now currently the president of the Manhattan-based Wenner-Gren Foundation for Anthropological Research. Overall, Aiello has had 21 publications in the fields of physiology, anatomy, and archaeology (under anthropology). She also has collaborated with 25 co-authors between 1981 and 2010.
Aiello studies evolutionary anthropology with focuses on human adaptation and life history, as well as the evolution of the brain, diet, language and cognition, and locomotion and its energetic costs. She has also researched Paleolithic hominids and their thermoregulation and climate adaptation.
In collaboration with Peter Wheeler she developed the Expensive Tissue Hypothesis, regarding early humans, according to which there is an inverse correlation between the increase in brain size during human evolution and the parallel reduction of the digestive tract as a result of richer protein animal foods. Another idea she posited, was that higher reproductive costs would be the effect of this increase in brain size, which was compensated by the females increasing in size faster than the males. She highlighted that terrestriality (movement of early hominids from forest to savannahs) is the oldest stage that led to human civilization. The second stage was bipedialism and the third is encephalization (evoking larger brains). Aiello identified social implications of meat eating; one of which is food sharing, which does not happen often in primates, which strengthens the bond between female and offspring. The other societal implication is that meat eating likely led to division of labor between males and females (males hunting, females caring for dependent young). Meat eating did not cause larger brains, but simply made them possible.
Further, Aiello emphasized that large brain, long legs, creation and use of tools, probably evolved together, but not as a single package at the beginning of the lineage of Homo, especially in Australopithecus ancestors. Therefore, early humans were able to change with their changing environmental conditions, which allowed them to survive and spread from Africa around 1.85 million years ago. Aiello has said, "taken together, these data suggest that species of early Homo were more flexible in their dietary choices than other species." And, "their flexible diet—probably containing meat—was aided by stone tool-assisted foraging that allowed our ancestors to exploit a range of resources." Flexibility is a hallmark of human biology.
Aiello is currently the president of this foundation. It was founded to support anthropological research in human origins, in 1941 in New York City, New York. Every year it gives out a total of $5 million in grants to further this research. "One of the real welcome trends in the field has been integrating other lines of study … to give us a much richer understanding of early humans." It founded the journal Current Anthropology, and continues to publish it as well. This foundation seeks to support all areas of anthropology and other related disciplines that are concerned with human development, origins, and variation.
Aiello is currently the President of the American Association of Physical Anthropologists (AAPA). In 2016 she received the Gabriel W Lasker Service Award in recognition of excellence in service to the AAPA, its members and the field of Physical Anthropology.