Primates show a remarkable ability to modify their behavior to accommodate their physical disabilities and impairments, according to a new literature review by Concordia researchers.

Whether disabilities are the result of birth defects or injuries, many primate species have demonstrated behavioral flexibility and innovation to compensate for their disabilities. They also benefit from their mothers’ flexible and innovative behavior early in life and from their peers in the population group as they age.

Researchers at the Primatology and Interdisciplinary Environmental Studies (PIES) lab looked at 114 studies and published their findings. American Journal of Primatology.

The survey also revealed something the researchers didn’t expect.

“Brogan Stewart, a PhD candidate and lead author of the paper, noticed that a large proportion of the papers cited human activity as a potential or actual cause of the disturbance,” co-corresponding author Sarah Turner said. says, who is an associate professor. Department of Geography, Planning and Environment in the Faculty of Arts and Science.

“Disability may be the result of other animals being trapped, or farmers trying to forage crops. It may be the result of vehicle collisions, or sometimes there are links between small population genetics and defects. are, or diseases spread by people or pollutants in the environment.”

Individual and group efforts.

The study consulted between 1931 and 2023 and identified 125 species. Chimpanzees were the most studied, accounting for 25 percent of the subjects. Other frequently recognized species include Japanese macaques, rhesus macaques, crab-eating macaques, and olive baboons.

More than 90 percent of disabilities were identified as impairments, injuries, or illnesses or conditions. Macaques were the subjects of the largest number of studies on impairment, while chimpanzees were the most studied on injuries and disease or conditions.

The researchers identified three themes in the literature they surveyed:

  • The main character of Behavioral flexibility: Despite being physically maimed or maimed, primates were able to adapt their species-specific behaviors to survive, reproduce, and thrive. For example, some chimpanzees have been observed using two or three limbs for locomotion instead of their usual four.
  • The importance of Maternal and specialized care and social environment: While all primates need their mothers early in life, mothers of disabled children will provide additional care and modify their behavior to meet the needs of their offspring. Likewise, other people in their group will sometimes modify their own specific care to support a disabled participant. For example, an adult male Japanese macaque adopted a young orphaned disabled monkey and carried it with him, moving on three limbs as the group traveled.
  • Potential for innovation: Disabled primates were observed developing new ways to participate in grooming, carrying their offspring, and feeding. These usually involved new ways of using their limbs, such as pinching branches with their arms against their torsos for food.

For Turner and his team, the findings open up new avenues of research and provide valuable insight into the adaptive capacities of primates, their resilience and the many unexpected effects of human activities on nonhuman animals.

“Some of the individuals at the Awajishima Monkey Center, where we do our fieldwork, are very physically impaired, but they are living their lives and doing things that other monkeys do,” says Turner. “They find ways to modify their behavior such as unique patterns of locomotion, ways of carrying their newborns, foraging and feeding techniques and individual styles of social grooming — to compensate for physical defects. took.”

Stewart adds, “We’re left to wonder if there’s a cost to the physical impairments for them? And when they’re compensating for them, is there a cost? The associated behavioral patterns in I am doing my PhD research on complexity. Physical impairment with Japanese macaques. Hopefully this research will give us more insight into the consequences of disability for free-ranging and wild primates.”

PIES lab members Megan Joyce (PhD student), Jack Cregan (MSc student), Stephanie Eccles (PhD student) and Michaela Gerung (PhD student) are also co-authors on the study. She was cooperating.