This article is taken from the n ° 203 of Sciences et Avenir “The essentials”, dated October / December 2020.
Koalas are the heaviest sleepers
Koalas sleep 20 to 22 hours a day. In question: their diet mainly composed of eucalyptus leaves, which requires a high expenditure of energy to digest their toxins and fibers. In addition, the low calorific output of this food leads them to save their energy. Just behind, armadillos, bats, possums and pythons, meanwhile, need 18 to 20 hours of rest.
Giraffes are the smallest sleepers
Giraffes only sleep two hours in a row! While in reality it allows itself 4 to 5 hours of daily rest, this herbivorous mammal does so in mini-naps – the longest not exceeding two hours – often at night. Over five meters tall, the giraffe is indeed easy to spot prey. In addition, she sleeps standing up, because of her difficulty in getting up quickly, which is probably fatal in the event of an attack. Only very young giraffes lie on the ground, a practice that they gradually give up as they grow older.
For the same reasons, the elephant and the horse only sleep two to three hours a day, usually standing up!