How_It_Works_Issue_99_2017

DID YOU KNOW? The olm is the national animal of Slovenia. These little amphibians are also known as baby dragons
Inside the belly
of the beast
With a super creepy extendable
stomach, the black swallower is a
fearsome denizen of the deep
Spiny palate
Sharp teeth on the
swallower’s jaws and
palate can be pushed
inwards to allow prey
to pass but then
prevent its escape.
Specialised gut
One fish was found in 2007 with
an 86-centimetre snake
mackerel in its gut – over four
times the length of the fish itself.
Giant teeth
Several large, hooked
front teeth help the fish
force large prey items
down its gullet.
Huge mouth
Large jaws open wide
to accommodate
super-large prey.
Black swallowers
This small fish looks like a creature that
nightmares are made of. It’s creepy, slimy and
lives in the inky blackness of the bathypelagic
zone. Sometimes, it can quite literally explode.
This is the black swallower, whose party trick
is its expandable stomach. Hanging beneath
the 25-centimetre fish like a balloon, this
stomach can stretch to the point of
transparency to accommodate huge meals.
Feasting on bony fish up to twice its length
and ten times its own weight, the swallower
uses a similar technique to a snake to cram it
all in; opening its mouth wide, it uses
razor-sharp teeth to ‘walk’ its mouth over the
prey. The evolutionary advantage of this is to
make food last longer. In the deep there’s not
much prey to be found, so eating a large meal
is an efficient way of conserving energy.
However, if a black swallower overindulges,
it can spell trouble. Its large, stretched
stomach can split. Sometimes, if a meal is too
large it can’t be digested quickly enough, and
so it starts to decompose in the stomach. The
gases produced by this can cause the
swallower to inflate and burst and the dead
fish floats to the surface.
This freaky fish is found in the tropical and
subtropical Atlantic Ocean
Chinese water deer
These cute-looking ‘vampire’ deer are vulnerable in
their native habitat along the banks of China’s
Yangtze River, yet they are surprisingly common in
the UK’s countryside, having been introduced by the
Duke of Bedford in 1896. They might look cute and
fluffy, but these deer are one of the most primitive
species, and the males have giant tusks that grow
from their upper jaws instead of antlers. These tusks
have a slight degree of movement, so they can be
pulled back when the deer is grazing. The length of
these canine teeth is a good indicator of age, with
most reaching full length by two years of age. The
fearsome-looking fangs are mostly used for settling
scores between males.
“ The black swallower is a
fish that can sometimes,
quite literally, explode”
Eternal fish
The immortal jellyfish is
thought to be just that
– it reverts back to its
juvenile stage and grows
up over and over again.
Long-knecked antelope
Also known as the ‘giraffe deer’,
the gerenuk uses its elongated
neck to reach leaves.
Deers once had antlers and tusks. The
small species retained the tusks, but
larger species only have antlers now
Tallest wild canid
This leggy canine is the
maned wolf, found in the
grasslands and scrub
forests of South America.
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