Animals Through the Night: Sleepover at the Zoo

Liz Bonnin and a team of experts who spent a time in Bristol zoo and in other places around the world trying to discover what animals do during the night. Do they dream? What is the rule of sleep in the animal kingdom?

Bristol zoo hosted the research team who planted 9 vision cameras with 6 kilo of cables to connect to the HQ. They started when the last visitor lift at 5 pm.

Animals differ in the way they sleep and the time they spend sleeping. They are divided into four sleep patterns: diurnal, nocturnal, crepuscular, and cathemeral. Human is diurnal animal who active during the day and sleep at night. Gorilla, Flamingo, and seals follow the same pattern. Nocturnal animals have an opposite pattern; they active at night and sleep during the day, Such as red panda, sloths, and crocodile. Crepuscular animals, such as capybara, tapirs, and bats, are active during the down and dusk.  Cathemeral animals are active every time. Lion fits in this pattern.

Animals differ in the way they sleep and the time they spend sleeping. Giraffe sleeps 4 hours a day, while brown bats sleep nearly 20 hours. They differ in the way they sleep some of them vertically such as leaf-tailed gecko. Zebra sleeps standing. Sloth sleeps hanging on tree’s branch. Dolphin sleeps hemispheric with one eye opens. On the other hands there is the seal that can sleep inside the water hemispheric, but on the land it can sleep bi-hemisphere. Ostrich sleeps sitting with opened eyes during what is called slow-wave sleep, but their eyes close when they go in Rem-sleep. It is the only specie that can be noticed while transferring from non-rem-sleep to rem-sleep. Octopuses change its color while sleeping. Some animals notice the cameras, such as the hippo which will not be a part of the study, and refused to come to their sleep places, even after the cameras were removed. The researchers have noticed that gorilla prepare its bed before sleeping which takes her about half an hour.

There are three essential elements tell the species when to sleep. The first is lightness and darkness. The second is the master body clock that tells the brain when to sleep. The third is the pressure of sleep when specie spends much time awake. Ants use guards to stay at the entrance of the nest to prevent any strangers. It has been stated that gorilla and lion sleep over 8 hours each day. Gorilla is considered to be a monophasic sleeper that when awakes during its sleep, it sleeps again. while the lion which is counted as a polyphasic sleeper that walks up and plays for a while then sleeps a gain.