NEW YORK — Alison Jolly, an American-born primatologist whose research in the forests of Madagascar shed light on the evolution of social intelligence and helped disprove a longstanding tenet that males were dominant in every primate species, died Feb. 6 of breast cancer in Lewes, England. She was 76.
Mrs. Jolly’s two major insights emerged from her 1960s field studies of the lemur, a primate whose development in isolation on the island of Madagascar makes the species akin to a living fossil. Mrs. Jolly cited lemurs’ complex social relationships as evidence of an unexplored trail in one of anthropology’s great mysteries: the evolution of higher intelligence.
Writing in the journal Science in 1966, she suggested that the many hours lemurs spent in play, mutual grooming, and social networking — activities that establish the social ties and hierarchies that determine access to food, mate selection, and migration patterns — may have been as important to the evolution of intelligence as the development of weapons and tools of hunting and protection, then considered the hallmarks of evolutionary advance.
More unnerving to colleagues was her finding that in some primate species, females run the show. The discovery upended a bedrock assertion in evolutionary biology — based on studies of chimpanzees and orangutans in captivity — that males dominated females in every primate species.
“Females have social, spatial, and feeding priority over males,” Mrs. Jolly wrote in describing the feeding, mating, child-rearing and recreational habits of the ring-tailed lemur, one of about 100 recognized species of lemur, of which more than a dozen are female-dominant. Among the ring-tailed lemurs, Mrs. Jolly wrote in “Lemur Behavior: A Madagascar Field Study,” “all females, whether dominant or subordinate in the female hierarchy, are dominant over males.”
The most subordinate females would “at times pounce upon a dominant male and snatch a tamarind pod from his hand, cuffing him over the ear in the process,” she added.
Mrs. Jolly’s findings were eventually accepted, but not without resistance, said Patricia C. Wright, a primatologist, lemur expert, and professor of anthropology at Stony Brook University on Long Island.
“This was a real surprise to people in the ’60s,” Wright said. “Female leaders were still so rare. And here comes a woman presenting a model of primates where the females are leaders — effective leaders.”
Mrs. Jolly, who wrote a six books while teaching and raising four children, variously did her research under the aegis of the New York Zoological Society, now called the Wildlife Conservation Society; Rockefeller and Princeton universities; and the universities of Cambridge and Sussex in England. She was considered rare among figures of her prominence in never having sought a tenured university post. At her death, she was a visiting scientist at Sussex.
Colleagues described Mrs. Jolly as a quiet path maker. She received less attention than contemporaries such as primatologist Jane Goodall, even though she helped change the field and pioneered a brand of environmental activism that has helped preserve vast, fecund swaths of Madagascar.
Mrs. Jolly persuaded Madagascar’s frequently unstable governments to expand wilderness preserves that are home to lemurs and thousands of other species of animals and plants found nowhere else. A native of Ithaca, N.Y. who received her doctorate in zoology from Yale University, she also wrote a series of children’s books in hopes of raising environmental awareness.