Animals sleep to save energy, rest their muscles, and allow
their brains to process the information that they pick up while
awake. Some hunting animals sleep a lot, because they devote
only a few hours each day to looking for food. Animals that are
hunted spend much more of their time awake and alert.Sleep
(^1) Bats sleep for about 20 hours a
day, often in large colonies.
(^2) Two-toed sloths are awake for
only four hours a day. Like bats,
they can cling to branches with
their claws while fast asleep.
(^3) Gorillas like to have about 12
hours of sleep a day.
(^4) Horses need just three hours of
sleep a day.
(^5) Elephants stand up for two of
the four hours a day they sleep.
They have to lie down for the
dreaming stage, when their
muscles are too relaxed for them
to stay on their feet. Large plant-
eating animals tend to get less
sleep than smaller animals, because
they have to spend so much time
looking for food and eating.
(^6) Seals often sleep on rocks and
beaches, but they can also
sleep floating upright at
sea, or even underwater,
surfacing to breathe
without waking up.
(^7) Wolves may sleep
for up to 14 hours a
day, especially if they
have had a big meal
after a successful hunt.
(^8) Pigs need eight hours of sleep
a day, just like adult humans.
(^9) Bears also clock up about
eight hours of sleep a day.
(^10) Tigers sleep for up to 16
hours, since they can catch all
the food they need within a
very short time.
Seals sleep for
around six hours
every day
56
(^14) Human babies need 15 hours of
sleep a day. We sleep less as we get
older, so adults sleep for an
average of eight hours, and elderly
people for less than six hours.
(^15) Echidnas are egg-laying
mammals that sleep for about
14 hours a day. Scientists believe
they do not have phases of dream
sleep like other mammals.
(^16) Red foxes sleep for about 10
hours, mostly during the day. Like
many hunters they are more active
at night when they track their prey
using their sensitive noses and ears.
(^11) Sheep are descended from wild
animals that needed to stay awake
to escape predators, so they sleep
for less than four hours a day.
(^12) Kinkajous are raccoon-like
animals that forage for food at
night, and sleep all day for about
12 hours.
(^13) Armadillos sleep for
18 hours a day, curled
up in their burrows.
Bats sleep while hanging
upside down by their
feet in caves, tunnels,
cellars, and from trees
7
6
23
22 24
11
3
21
14
1
8
056_057_Sleep.indd 56 03/01/19 12:09 PM