July 8 – Bite me!

Today’s factismal: The flesh of the sharpnose sevengill shark is mildly poisonous.

One of the most popular dishes in the world is “shark fin soup”. Eaten by connoisseurs across the globe, it is made by catching a shark, chopping off the fins, and tossing the rest of the critter overboard to die. It is generally made from sharks such as the thresher, the basking, and the whale shark. But if those critters were more like their sevengill cousins, then odds are you’d never see the dish on a menu. That’s because the broadnose sevengill shark is vicious even in death, snapping and biting at anything and everything in reach, and the sharpnose sevengill shark has poisonous flesh.

A shaprnose sevengill shark (Image courtesy Encyclopedia of Life)

A shaprnose sevengill shark
(Image courtesy Encyclopedia of Life)

The sevengill sharks are one of the older branches of the shark family, and are limited to the two living members. Like all old families, they’ve got some peculiarities that sometimes scare the neighbors. The most obvious of these is the number of gill slits: where a normal shark has five, the sevengill has (you guessed it!) seven. Another of their oddities is their willingness to eat anything, from squid to fish to clams to other sharks to the fisherman trying to catch them. In addition, these critters prefer the deeper waters off the continental shelf to the coastal shallows where prey is abundant; by being the biggest shark in the room, they are able to eat more with less danger.

A broadnose sevengill shark (Image courtesy Encyclopedia of Life)

A broadnose sevengill shark
(Image courtesy Encyclopedia of Life)

Of course, that makes sightings of this shark fairly rare. Though they are sometimes seen in trawler nets as bycatch, the most common way to see them (outside of an aquarium) is to be a scuba diver. Because the sevengill sharks move into shallower waters at night, following the squid and other critters that they feed on, they are sometimes seen by scuba divers. Because the sightings are so rare, researchers are still unsure of how many sevengill sharks are out there and what their habits are like. And that makes any observations that you happen to make all the more valuable. If you do see a sevengill shark, then please report it at Sevengill Shark Sightings:

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