Group sleeping can impact when animals sleep, how long they sleep for, and how deeply they sleep. For example, groups of meerkats time their sleep according to 'sleep traditions'; olive baboons sleep less when their group size increases; bumblebees suppress sleep in the presence of offspring; and co-sleeping mice can experience synchronized REM sleep. To fully understand both sleep and animal social structures, we need to pay more attention to the 'social side' of sleep, animal behaviorists argue.
