Why do deep sea creatures look like they crawled
out of our nightmares?
I’m Anna Rothschild, and this is Gross Science.
Up near the surface of the ocean, where sunlight
trickles down into the water, you see some
of the world’s most gorgeous marine life,
like schools of tropical fish in coral reefs.
But once you dive down towards the aphotic
zone—deep enough that there’s very little
sunlight—the environment gets much harsher,
putting some unique pressures on the creatures
that live there.
And that’s led to some pretty weird adaptations.
For example, food is scarce at the bottom
of the sea.
Because sunlight doesn’t reach that far
down, there’s no photosynthesis.
In other words, there are no creatures taking
light and turning it into energy.
So almost everything down there is a consumer.
Some animals survive by eating “marine snow,”
which is organic stuff (mostly like dead things
and poop) which sink down from above.
But others adapt to become vicious predators.
Take the female anglerfish.
It lies in wait to conserve energy and uses
a bioluminescent lure (essentially a spine
with a light-producing organ called a photophore
at the end) to attract unwitting fish.
It has sharp snaggleteeth to make sure prey
don’t escape, and it can extend its jaws
and stomach to swallow prey up to twice its
length.
That way, if it is lucky enough to find food,
it can stock up.
There’s also massive water pressure when
you get down that deep.
You’ve probably heard of the blobfish, which
looks like a pile of goo when it’s out of
water.
But this gelatinous, low-density flesh helps
it stay buoyant, or float, when it’s under
extreme pressure.
Then, there’s the darkness, which makes
it almost impossible to see.
Some deep sea creatures have tiny eyes with
huge pupils to detect bioluminescent flashes
of predators, prey, or mates.
Other animals are virtually blind, like the
tripod fish, which has to rely on extra-long,
extra-sensitive fins to detect small movements
in the surrounding water.
In addition to scarce food, extreme pressure,
and darkness, another major environmental
factor is the cold temperature of the deep
sea.
And scientists think that some combination
of these conditions may have led to deep sea
gigantism.
Organisms like giant isopods, Japanese spider
crabs, and colossal squid could rely on their
large size to better regulate their body temperature
and slowing down their metabolisms.
There’s something creepily alien about deep
sea creatures, but all their crazy adaptations
help them survive in an environment that’s
not really suited for life as we know it.
Oceans cover about 70% of our planet, but
only about 5% of them have been explored.
So who knows what other weird creatures might
be lurking in those depths?
Ew.
