Primates Chimpanzees sleep longer in a group than alone
Chimpanzees sleep longer when they are in a group than when they are resting alone - in contrast to other primates. In addition, the sleep duration of individual chimpanzees varies greatly depending on the composition of the group.
15.12.2025, 10:44
SDA
This is shown by a study led by the Laboratory of Comparative Cognition at the University of Neuchâtel (Unine) on the sleeping behavior of chimpanzees in their natural habitat. It is the first study to measure the sleep of an ape directly in the wild.
It confirms that the duration, fragmentation and temporal structure of sleep are strongly dependent on the social context. In many animal species, sleep can be seen as a biological compromise.
On the one hand, it brings numerous benefits to the organism, for example by strengthening the immune system and improving cognitive abilities. On the other hand, sleep prevents vital activities such as foraging, reproduction, avoiding predators or interacting with other group members.
"It can therefore be assumed that animals adapt their sleep according to the costs and benefits of the respective situation. Especially in social species, the social context can influence sleep," Clara Hozer, primatologist at Unine and co-author of the study, is quoted in the press release published on Monday
"We still know very little about the sleep of chimpanzees - one of our closest relatives - in their natural habitat," added the researcher. "Knowledge has so far been limited to the daily construction of a sleeping nest. The influence of social factors, on the other hand, had never been investigated."
Field research in Uganda
To close this knowledge gap, Hozer and her team spent more than a year observing a community of wild chimpanzees in the Budongo forest in Uganda.
The first key observation: high-ranking males slept for shorter periods and were more restless than lower-ranking males. This effect depended on the number of males present during the night.
"The more males were present, the less the dominant animals slept", according to the study published in the journal "Current Biology". This could be explained by increased vigilance within the group or by competitive pressure, as dominant males wake up more often to keep an eye on potential rivals.
In addition, the researchers found that chimpanzees sleep on average around 20 minutes longer per night when they sleep in a group rather than alone. This is despite the fact that group sleep led to females going to bed later and all individuals waking up earlier.
