W*****B
发帖数: 4796 | 1 I Weird & Wild I
Octopus Chokes Dolphin to Death in First-Ever Discovery
The young male, Gilligan, was in otherwise perfect condition, a new study
says.
Nobody ever told Gilligan the dolphin not to bite off more than he could
chew.
The male Indo-Pacific bottlenose dolphin is the first known cetacean to die
from asphyxiation by octopus, a new study says.
He "seems to have been extremely greedy and thought, 'You know what,
I’m going to swallow it whole,'" says study leader Nahiid Stephens
, a pathologist at Murdoch University in Perth, Australia.
When the young male, found on a beach about two hours south of Perth, was
brought to Stephens' lab for a post-mortem in August 2015, bits of a
Maori octopus were still hanging out of his mouth. (Read why octopuses
remind us so much of ourselves.)
Other dolphins have been observed killing and eating octopi before, so
Stephens conducted a post-mortem to figure out what went wrong—particularly
because the animal, nicknamed Gilligan, was in amazing condition. First,
she had to remove the octopus.
"It really was a huge octopus, I just kept pulling and pulling and
thought, 'My god! It's still coming,'" Stephens says, adding
that it had a tentacle span of 4.2 feet.
The autopsy, described in a recent study in the journal Marine Mammal
Science, revealed that the problem arose when Gilligan was swallowing what
would be his last meal.
Dolphins can disengage their epiglottis—a flap of tissue that connects the
larynx to the blowhole—to open up their throats and swallow larger pieces
of food.
Stephens says that the 4.6-pound cephalopod appeared to have grabbed onto
Gilligan's larynx with a tentacle, preventing it from reconnecting to
the dolphin's breathing apparatus and effectively suffocating him to
death.
"That octopus might have been, in theory, dead, but the sucker was still
functional," Stephens says, adding that while nobody wins in a
situation like this, "the octopus gets a bit of a last hurrah."
Playing With Their Food
Kate Sprogis, a research fellow at Murdoch University, says an octopus is &#
34;not easy prey to just swallow."
While studying the dolphin population near Bunbury, where Gilligan died,
Sprogis has observed dolphins tossing octopi in the air in an attempt to
tenderize the invertebrates—breaking them up into smaller, more digestible
pieces.
A cetacean will often breach the surface and send the octopus flying through
the air—quite the spectacle, according to Sprogis, who wasn't involved
in the new study.
"It's quite energetically demanding for the dolphins," she says,
adding the unhappy cephalopods will try to cling to the dolphins' heads
. The sheer effort required is "why we think the octopus is highly
nutritious."
After throwing their prey around, the dolphin usually bites off the octopus&
#39; head—though the battle is far from over, since its arms can remain
active for some time. (Related: "Why These Dolphins Behead Their Prey.&#
34;)
As for Gilligan, "he obviously didn't toss it enough, and got a bit
cocky and swallowed it," Sprogis says.
Learning From Tragedy
While Gilligan's unique death may have been a first as far as scientists
are concerned, it likely happens more frequently in nature.
Historic seafarers told stories of sperm whales battling krakens—likely
just misunderstood fights between giant octopi and sperm whales, Stephens
says.
Gilligan's situation is "an interesting way of highlighting the
things that happen in our backyard all the time that we're not really
aware of," she says. (See 10 intimate photos of dolphins around the
world.)
Not only that, but the dolphin's unfortunate end helps scientists learn
more about the animals and their biology. As a young healthy male, Gilligan
is also an important counterpoint to many of the sick, old biological
samples that pathologists often encounter.
"These opportunities don’t come up that often," Stephens says, "
;so the more we can visualize these individuals after the unfortunate,
tragic event of their death, the better it is."
_ |
|
