Monkeys keep pets and maintain friendships with other animals
This behaviour may shed light on one of the defining features of our own species: our extraordinary relationships with other animals
In a study of primate interactions with other animal species, researchers uncovered a broader pattern than previously known. Over 427 documented cases from the 1970s to 2025 revealed that primates frequently keep pets and maintain friendships with other animals. This behavior may provide insights into one of the defining features of human species relationships: our extraordinary connections with other animals.
The study analyzed social interactions involving 88 primate species and their interactions with 127 other animal species. Common behaviors included play and grooming, but instances of primates carrying, huddling, sharing food with, and occasionally adopting members of another species were also observed. These interactions were mostly initiated by the primates themselves.
Examples of such relationships include a northern white-cheeked gibbon at the Shanghai Zoo holding and caressing a mouse, black-and-white snub-nosed monkeys playing with domestic pigs, a langur stroking a squirrel, a silverback gorilla cradling a tiny wild bushbaby, and bonobos gently holding mongoose pups. Some interactions provide benefits similar to those within primate species, while others suggest a broader capacity for social flexibility and tolerance towards other species.
The study found consistent patterns in who interacted, with young primates playing more with members of other species and adult females more involved in grooming. These findings mirror established age and sex differences in primate societies. While many interactions were relatively short-lived, some reports involved cases lasting for weeks, such as the adoption of a marmoset by a capuchin monkey.
However, not all interactions were positive. Some involved rough handling, neglect, injury, or death. Additionally, a small number of interactions were clearly abusive, involving violence. These unusual encounters occur across all major primate lineages and may offer valuable insights into primate behavior and social dynamics.
Written by urgent.news from Scientific American's reporting — not their text. Machine-written — it may contain errors, so check the original before relying on it.
