Professor at Leiden University

New sleep research Project by Postdoc Juan!

Sleep is something that you and I have in common with all other land animals – and possibly fish, insects, perhaps even worms. The fact that you and a frog both need to sleep points to an essential function – without sleep, our waking hours aren’t pleasant and everything starts to break down. While we know a lot of “maintenance” happens in our sleep, this behaviour with which we engage daily remains as familiar as it is mysterious. Dozens of labs today use extremely sophisticated equipment to map out the electric signals of our brains in our sleep, slowly hinting towards sleep’s involvement in tasks that go beyond maintaining our bodies, such as retaining memories, processing emotions, or even fending off predators. CoPAN postdoctoral researcher Juan Olvido believes that, by observing our great ape participants during their sleep, we can better understand its functions, how its healthy expression breaks down in some individuals, and how to intervene to restore healthy sleep patterns.

Zoo-housed animals are observed by visitors and closely monitored by professional caretakers throughout the day, but we know surprisingly little about their night lives. Deploying remote sensing technologies is allowing CoPAN to obtain long-term data about sleeping patterns at the group and individual levels. For example, by continuously recording audio during the night, it is possible to estimate sleep quality at the group level in a group of socially housed primates. Video monitoring can also track individuals to estimate the quality of their sleep. By comparing sleeping patterns between closely related species of great ape – humans, orangutans, chimpanzees and bonobos – we can make informed guesses about why we sleep like we do. Some researchers think, for example, that fragmented sleep is a remnant from the days when our ancestors slowly abandoned tree-living and increasingly became land-dwellers, making themselves more vulnerable to predators. Orangutans are tree-living, while chimpanzees sleep on the trees but may occasionally do so on land. If fragmented sleep helped our ancestors react to predators, we should expect orangutans to sleep throughout the night, and to see chimps wake up a few times in their sleep.

With the welfare of our nonhuman participants in mind, we have designed these sleepy observations to carry potential to enhance animal welfare. The science of animal welfare is in constant transformation and the last decades have resulted in the application of increasingly reliable tools to measure welfare. However, most of these remain time-consuming, costly, or logistically challenging. Observation requires long hours of highly trained researchers, and cortisol measurements are costly and interfere in the animals’ daily lives. Our methods are quantifiable, automatic, and absolutely do not interfere with our participants’ routines. Partnering institutions can easily make use of our data to better understand the needs and peculiarities of individuals under their care. Temperature, humidity, diet, changes in group composition, interventions, time of the year, etc. are known or suspected to affect sleep quality.

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