Page 95 - World of Animals - Issue #41

Animal answers

Which Lemurs are

most active
animals see in Inside an animal eye important they
during the
night, so it’s
The tapetum lucidum
Lens
enhances the light
the dark? Iris Retina entering the animal’s can fi nd their
way around
eye, allowing it to see
Pupil better in low light
It’s impossible to see the world through another Tapetum lucidum
animal’s eyes, and for many years scientists
believed most critters see in the same way Reflected Chorcid

humans do. However, a‡er many years of study, light
we now know that we have relatively poor vision
compared to lots of other species.
Many nocturnal animals have specially adapted Cornea
eyes, which allow them not only to see in the
dark, but also to see in colour. This special
adaptation comes in the form of the tapetum
lucidum, a special layer of tissue found at the
back of the retinas of some mammals. It acts

as an inbuilt reflector that enhances the light
entering the eye, giving the animal a greater
sensitivity in conditions of low light. This is a
common feature in many carnivores that need
the extra boost of light to see and stalk their
prey in the night. It’s also the reason your cat’s

eyes glow when light is reflected, as the tissue
contains minerals that reflect different colours

when light hits them.
Humans, and our primate cousins, don’t have
a tapetum lucidum, which is primarily why our
eyes aren’t as sensitive in the dark. However, it’s
not just predatory creatures, such as tigers, bats
and geckoes, that have this special skill, but also
animals wanting to avoid being eaten, such as
moths, lemurs, and goats.
Why can some while standing as getting
Many big birds sleep
animals sleep up from the floor would

take them too long in
standing up? an emergency

Some animals sleep standing up: not
because it’s comfortable, but because
they literally have no other choice. It’s
mostly the more awkward-looking
creatures that catch ‘forty winks’ on
their feet, because it means if they
need to make a speedy get away
from a predator, they don’t need to
fumble around before making a run
for it. A flamingo will fold its neck

neatly around and rest its head on © Thinkstock
its back as it snoozes, a sleeping

position also favoured by giraffes.
Horses, cows and zebras, however,
will just sleep in their normal posture,
making it more diffi cult for a predator

to know if they are awake and if it is
safe to strike or not.
One thing these animals all have in
common are knees that can lock into
place. If you were to try this, you’d
soon fall over, but these animals Q. Is legalising rhino horn
have legs that align vertically with the
ground, and so locking their knees the way to save the rhino?
requires little muscular effort.

Find out at…
animalanswers.co.uk

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