PROFESSOR
(Canadian): It’s a common myth that animals spend most of their time sleeping. This
is an especially common belief about pets such as cats and dogs. But while
there’s some truth to the fact that domesticated animals have a lot of time to
lounge around, that’s not necessarily representative of the sleep patterns of
animals in general. As we’re doing a survey of the animal kingdom in this
course, I thought it would be a nice break from the routine to stop and debunk
some of these animal sleep myths.
Let’s start with cats, since they probably have
the worst rap of all when it comes to sleep. Um, it’s not just house cats that
are thought to sleep excessively, but the big ones, like lions and tigers. The
rumour is that they are only awake for about four hours per day. But in fact, a
study of lions in South Africa showed that they are resting for an average of
14 hours per day. Lions, just like domesticated cats, are cathemeral, meaning
that they take short, sporadic naps throughout the day and night. When they
added up the hours of actual sleep for over 200 lions, they found that it was
far less than the myth suggests.
In fact, it’s actually brown bats that win the
prize for the most sleep. Those little guys can spend up to 20 hours of their
days dozing off. Ironically, the larger animals such as giraffes and elephants
need the least sleep, only four hours each night. Even though that seems
counterintuitive, it has been well documented in academic literature.
Here’s another one that cracks me up…that
albatrosses sleep while flying. I think this idea got started because
albatrosses fly long distances, covering thousands of kilometers over the open
sea before touching down on land. So people just assumed that they must sleep
while in flight. But a recent study revealed that it’s actually more likely
that many birds have evolved to be able to go without sleep for extended
periods of time.
Uh, I’ve also heard many people claim that
whales can dream just as humans. Well, not exactly. Whales are certainly
intelligent creatures, and their communication capacity far exceeds most
animals. However, if whales were able to dream, this would mean that they would
have to enter the REM phase, the deepest phase, of sleep. But marine mammals
don’t enter REM because they require regular muscle movement to return to the
surface for air. Some researchers think it’s possible that whales do enter REM
for very brief periods of time. But even if such were the case, it would likely
last for minutes at the most. Hardly enough time to dream.
Of
course, some marine mammals, such as sharks, don’t need to come to the surface
for air because they get oxygen differently. Uh, by forcing oxygenated
water over their gill slits. And how do they do that? By swimming. So if they
are swimming all of the time, they don’t sleep, right? Wrong. Because sleep in
many sharks is actually controlled by the spine and not the brain. Thus, sharks
can be unconscious even though they are moving. Interesting, no?