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Nature

Octopus Chokes Dolphin To Death In Bizarre Case

author

Aliyah Kovner

Science Writer

clockJan 18 2018, 17:29 UTC

Gilligan was discovered on Stratham Beach in Bunbury, Australia, with an octopus still sticking out of his mouth (August 2015). Photograph by John Symons/Murdoch University (First published in Marine Mammal Science)

When a dead marine mammal washes up on the shore, biologists will often perform a necropsy to determine the cause of the creature’s demise. But for Gilligan, an Indo-Pacific bottlenose dolphin found on a beach in Southwest Australia, there was a pretty obvious external clue.

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The young male cetacean was discovered with the tentacles of the Maori octopus he choked to death on still hanging out of his mouth.

In a case study published in Marine Mammal Science, lead author and pathologist Dr Nahiid Stephens from Murdoch University chronicles the bizarre and darkly comedic findings.

Describing the likely course of events during Gilligan’s last moments, Dr Stephens inferred to National Geographic that he “seems to have been extremely greedy and thought, ‘You know what, I’m going to swallow it whole.’”

Gilligan was discovered on Stratham Beach in Bunbury, Australia, with an octopus still sticking out of his mouth (August 2015). Photograph by John Symons/Murdoch University (First published in Marine Mammal Science)

Cephalopods are common prey for dolphins, but apparently this otherwise extremely healthy bottlenose simply forgot the necessity of chewing one’s food – particularly if said snack is a member of the third largest octopus species in the world, with a potential arm span of almost 2.1 meters (7 feet).  

Maori octopus (Macroctopus maorum). Saspotato/Flickr

During the post-mortem, Dr Stephens’ team observed that the octopus’s head had been severed and swallowed, but the arms had a hit a snag on their way down the hatch.

Like humans, dolphins have a protective tissue structure called the epiglottis in their throats that covers the opening to the airway, or larynx. When breathing, our epiglottis stands open to let air into the larynx, but when we eat, it pulls tight against the larynx's entrance to prevent food from entering.

Through chance (or perhaps some trickery from the octopodian great beyond), one 0.6-meter-long (2-foot-long) tentacle managed to adhere itself to the back of Gilligan’s mouth during the commotion, pinning the epiglottis in place and blocking the larynx. The seal created by the suckers was so strong that air trapped in the dolphin’s lungs didn’t escape until the biologists removed the tentacle’s suckers. The official cause of death was thus ruled as "non-drowning asphyxiation", or "death by octopus".

This photo shows the octopus in situ (ie as found upon dissecting the dolphin open) within the dolphin’s opened throat and proximal esophagus (beginning of esophagus). For scale, the wooden case identification marker measures 15 x 1.7 cm. Photograph by Dr Nahiid Stephens/Murdoch University (First published in Marine Mammal Science)

"That octopus might have been, in theory, dead, but the sucker was still functional," said Stephens. And though both animals departed, "the octopus gets a bit of a last hurrah."

If anyone is wondering how the subject of an undersea Darwin Awards scenario came to be named after a classic TV character, Seeker writes that Gilligan was actually part of a well-studied Indo-Pacific dolphin population. He was originally photographed and named by a group of researchers in 2007. It took until 2015 (when his body was found), however, for the tragic appropriateness of this moniker to reveal itself. Just like the titular character of Gilligan’s Island, this dolphin appeared prone to bad decisions.

[H/T: National Geographic


Nature
  • dolphin,

  • octopus,

  • suffocate,

  • bottlenose,

  • marine mammal,

  • choke,

  • necropsy