WASHINGTON — The octopus already is an oddball of
the ocean. Now biologists have rediscovered a species of that
eight-arm sea creature that's even stranger and shares some of our
social and mating habits.
With their shifting shapes, mesmerizing eyes, and uncanny
intelligence, octopuses "are one of the most mysterious and
captivating species," said Rich Ross, a senior biologist at the
California Academy of Sciences. "They're aliens alive on our planet
and it feels like they have plans."
For Ross and colleagues, it got stranger when they got a batch
of octopuses from Central America to study. The critters just
didn't fit the loner denizen-of-the-deep profile that scientists
had drawn for the rest of the 300 or so octopus species.
While most octopuses live alone, coming together for
ever-so-brief and dangerous mating, couples of this species can
live together to mate for a few days in the same cramped den or
shell.
While other male octopuses mate from a distance to avoid being
cannibalized, these octopuses mate entangled beak-to-beak. That
style could almost be thought of as romantic, said Alvaro Roura, an
octopus expert at La Trobe University in Australia, who wasn't part
of the study.
While other females lay one batch of eggs and then die, the
female of this species lives longer and produces eggs constantly,
bettering the species chance of survival, Ross said.
But it's more than sex. These octopuses clean out food waste
from their dens. They twirl their arms like an old-timey movie
villain with a moustache. And they quickly learn that people mean
food: when someone enters the room, they leave their dens and head
to the top of the tank.
"It's the most amazing octopus that I've ever gotten to work
with," Ross said.
The octopus, normally a dull chocolate brown, suddenly sports
stripes and spots when it gets excited or upset, said Roy Caldwell
of the University of California, Berkeley. He is the lead author of
a paper on the octopus with Ross and others published Wednesday in
the journal PLOS One.
The species is preliminarily called the Larger Pacific Striped
Octopus, although it's really not much bigger than a tennis ball —
just bigger than a similar species.
It was found almost 40 years ago off the coast of Panama. Other
scientists wouldn't believe it was a separate species or that it
showed such distinctive behavior. So its discoverer, Arcadio
Rodaniche, gave up and the species was never formally described or
named.
Then in 2011, Caldwell got an email from a high school student
about his pet octopus, Charlie. It was the same species discovered
in the 1970s. Caldwell traced it to a dealer who sent him two dozen
of the species from Panama, Nicaragua and Mexico to study in
captivity. The researchers note that this octopus species could act
differently in the wild.
They included Rodaniche as a co-author after the retired
researcher declined to let them name the octopus species after
him.
In the journal Nature, a different team of scientists on
Wednesday published the first map decoding octopus genes. They
found the octopus's genetic code is only slightly smaller than
humans, but twice as big as a bird's genetic instruction guide.
Octopuses are invertebrates, meaning they have no backbones.
Invertebrates generally have a less evolved nervous systems, but
not the octopus. They found that it had many of the same genes as
other invertebrates, although mixed up as through a blender, said
study author Clifton Ragsdale at the University of Chicago.
"There's a lot of weird creatures and these are the largest of
the weird creatures," he said.
