Pictured below is the body of a dead juvenile harbor porpoise. It washed ashore on September 3rd, 2011 in Oostende, Belgium. Perhaps you’ve noticed that this poor porpoise is missing a rather important part of its anatomy – mainly, the lower third of its head.
It wasn’t the victim of a shark or killer whale attack. It hadn’t been caught in razor wire or had a run-in with machete wielding pirates. No, researchers from the Royal Belgian Institute of Natural Sciences know exactly what caused these injuries, and it’s a slightly horrifying revelation. This porpoise had its throat ripped out by a gray seal.
You might recognize the gray seal as one of those fluffy beach-sausages that wildlife photographers can’t get enough of. Other than hard-hearted pelt-hunters, who couldn’t fall in love with these adorable little guys when they stare up with those kawaii anime eyes?
But they don’t stay cute forever. Eventually, they grow up. And in Belgium, they eventually acquire a taste for porpoise flesh.
Gray seals generally feed on fish and crustaceans, occasionally taking on species as large as salmon, which average about 75 cm in length. They have never been observed feeding on mammals, and certainly never large-ish mammals like the harbor porpoise, which can reach up to 2 meters in length. But the harbor porpoise found in Oostende, and another harbor porpoise found a few weeks later with part of its head missing, displayed injuries that are consistent with an attack by gray seals. Researchers found evidence that the seals grabbed on to the harbor porpoises with their flipper-claws and repeatedly tore into the porpoises’ head and neck with their powerful incisors. It’s entirely likely that the seals consumed some porpoise flesh before swimming off. So there’s a happy ending insofar as it wasn’t just a random act of interspecies violence; the seals did get a meal out of the encounter.
Predation attempts like this have never been witnessed before in gray seals, which makes this a novel discovery. The question is, why? Why now? What has happened to the gray seal population in the North Sea that has given them a taste for porpoise flesh? The answer: nobody knows. Researchers suggest that “it may indicate bottom-up changes in trophic structures instigated by changes in the ecosystem.” Or, it might be a sign of the coming zombie apocalypse. Imagine a scenario where these seals have been infected with a zombic-virus that gives them an uncontrollable urge to tear into the flesh of other marine mammals. Like seals on bath salts! Imagine if this virus jumps to humans! Imagine, if you will, that the end of the world begins with Porpoise Zero from Oostende.
I don’t want to alarm you, but I would just like to point out that this Mayan calendar shows an image of what is clearly a grey seal (or possibly a harbor seal or that thing that jumps out of that guy’s chest in Alien) with jaws agape, ready to tear into porpoise (or human) flesh.
Oh, and if you want to read the original article concerning this incident (devoid of zombie and Mayan references), here’s the full citation:
Haelters, J. (2012). The Grey Seal (Halichoerus grypus) as a Predator of Harbour Porpoises (Phocoena phocoena)? Aquatic Mammals, 38 (4), 343-353 DOI: 10.1578/AM.38.4.2012.343
Noc The Talking Beluga Next Post:
Advice to students wishing to study dolphins and other marine mammals