[MUSIC PLAYING]
SPEAKER 1: They can crawl.
They can squeeze and hide.
They can even use jet propulsion.
And just when you think that octopuses couldn't
get any more versatile, they up and walk away. [MUSIC PLAYING]
And while it's utterly absurd to look at, once we stop laughing,
maybe we should ask why would one of the most agile creatures
in the ocean choose to scamper.
Backwards.
That momentous question captured the attention
of Dr. Chrissy Huffard, a Senior Researcher at the Monterey Bay
Research Institute, whose graduate studies at UC Berkeley
focused on cephalopod behavior.
DR. CHRISSY HUFFARD: Generally, I
try to understand how octopuses survive
in their everyday lives, avoid being eaten,
find mates, and find prey.
SPEAKER 1: Documenting the survival strategies
of octopuses isn't easy.
You've got to be willing to spend a lot of time
on remote tropical beaches.
DR. CHRISSY HUFFARD: My job is a lot of fun.
I wake up at dawn every morning, get in the water,
and get out for a brief snack at low tide,
and then get back in until sunset.
SPEAKER 1: It's hard work, but somebody's got to do it.
DR. CHRISSY HUFFARD: Unlike other octopus studies
that had been done, I was actually
able to follow individuals all day long on snorkel.
SPEAKER 1: Particularly, the cryptic algae octopus.
DR. CHRISSY HUFFARD: The algae octopus
tends to come out during times of day and tides,
and in certain habitats that mean
they tend to clump in the wild.
And there are lots of individuals
that use the same area and prefer that same area.
So they're bumping into each other, mating,
fighting, competing for similar resources.
And I could watch this happen in real time
and pretending I wasn't there.
SPEAKER 1: Although on occasions, her subjects
realized they were being observed.
DR. CHRISSY HUFFARD: I am assuming that they considered
me a predator in those cases.
Octopus's main defense is not to be seen in the first place.
That's their best chance of not being eaten.
SPEAKER 1: And if all else fails, they can just jet away.
SPEAKER 1: And in that shape, camouflage
isn't even a possibility.
SPEAKER 1: It was in one of these defensive moments
that Dr. Huffard witnessed an entirely novel
attempted escape.
DR. CHRISSY HUFFARD: I was working
with a film crew for a documentary series called
the Shape of Life.
It was easy to get them to act defensively
when you're chasing them with a camera,
and we got footage of the coconut octopus walking
on two arms.
Oh, it was hysterical to see.
We laughed and our masks filled up a little bit with water.
Then later I saw the behavior in the algae octopus.
We again laughed at how hysterical it looked,
but also we understood the biomechanic significance of it.
Octopuses have very strong arms even
though they don't have bones.
They have three bands of muscles that oppose against each other.
And the volume of those muscles and their arms
stays constant as it changes shape.
That's called a hydrostatic skeleton.
That allows them to use the internal pressure of their arms
for support.
SPEAKER 1: But just because an octopus is physiologically
capable of walking backwards, doesn't make it
the best form of escape.
Or does it?
DR. CHRISSY HUFFARD: When octopuses jet
to escape a predator, there's so much
internal pressure that's built up inside
of their mantle cavity, or inside of their body sac,
that it actually stops their hearts briefly.
SPEAKER 1: Going into cardiac arrest
while swimming away in a panic, probably isn't ideal.
DR. CHRISSY HUFFARD: Walking backward
allows them to use two of their arms for locomotion
and six of their arms for camouflage
or to otherwise make their shape seem unrecognizable.
SPEAKER 1: And while only a few species thus far
have been documented fleeing on foot or rather arms,
Dr. Huffard believes that this escape plan isn't
a difficult trick to pull off.
DR. CHRISSY HUFFARD: Just the way
we don't have to stop and think move left leg,
move right leg, it's a type of motion called feed forward
movement, where it's almost automatic once it gets going.
And I think it was part of their normal locomotion repertoire
of how they can move around.
SPEAKER 1: Yet another method for
these skittish invertebrates to show off having no backbone.
For Science Friday, I'm Luke Groskin.