Showing posts with label chondricthys. Show all posts
Showing posts with label chondricthys. Show all posts

Shark Week: Nurse Shark.

This is a weird shark week. That means we'll be going off the beaten path, looking at sharks you never knew existed. Not every shark can be Jaws, so how about we switch to something more docile, yes?



This is a nurse shark (Ginglymostoma cirratum). Nurse sharks are fond of shallow, warm waters in the Pacific and Atlantic Oceans. They aren't dangerous to humans unless you disturb them, in which case prepare for a nasty bite from thousands of needle teeth. Small stuff on the bottom, be it fish, crustacean, or mollusc, is not so lucky. Their barbs function much like the whiskers on a catfish, meaning that stuff beneath the sand is not safe.

Nobody really knows why these sharks are called nurse sharks. They don't take particularly good care of their (!live) babies. The name could come from the shark's docile nature or how it "nurses" the sea bottom with its mouth, but the most likely explanation is the Old English "hurse," meaning this particular type of bottom-dwelling sea shark. In other words, name change via spell check. We've all been there.



Now, here's a puzzle: How do bottom-dwelling sharks, well, stay on the bottom? Most sharks need to swim constantly to circulate water across their gills.Nurse sharks circulate water by pumping it through their mouths. These sharks do rest a lot, sometimes on top of each other. They can be seen sleeping in masses of up to 30-40 members in one spot, meaning that these are relatively social sharks. How far removed is that from a terrifying great white?

In many ways, nurse sharks are the "Burmese pythons" of the saltwater aquarium trade. People see a cute juvenile, don't think it'll get very big, then wind up with a 10+ foot shark that no tank will hold. Good luck finding a home for a shark; most aquariums will not take them. Please do your homework before taking home any animal, especially a shark!

Creature Feature: Basking Shark.

So, wait a tic. Is hakarl made of basking shark or Greenland shark? Actually, this is where the video got something wrong: basking sharks aren't poisonous. They can still be used for hakarl, but the curing does little more than make the meat extra-pungent. What is a basking shark, anyways, because the image of a shark basking sounds like something off of a cheap beach souvenir?

Source.



This is what a basking shark looks like. It is native to all the seven seas, presumably following the  plankton by smell. Being large, slow-moving, and calm, it has been a fishery staple for quite some time. It is the second largest fish in the world after the whale shark.

These sharks are big. You thought 23 feet was big? Nah, the basking shark can get up to 40 feet long. To reuse a bad joke, that's a lotta fish; it makes sense that some Vikings would want to preserve that. Numbers like that have not been seen for a while, but remember that the basking shark is kind of like a whale shark. Yes, it is similar to something with whale in is name for so many reasons.

Source: BBC, but sharks aren't mammals, silly network.


The basking shark, like the whale shark, is a filter-feeding shark. It eats whatever small things it swims through. That means it is only a threat to the tiny little creatures (zooplankton) that get caught in the basking shark's super-large mouth. Even though it may look a lot like a great white, it's not going to bite you. I would not, however, suggest going up to random large sharks and testing this.

Alas, this is another one of those creatures that is at risk of going extinct. Shark fin soup can come from these sharks, too. Shark liver oil was once popular, and Japan uses parts of this shark as an aphrodisiac. Basking sharks were once so common that they were thought pests. Now some areas ban catching them while others seem to have lost them entirely. If you see one of those sea monsters, look on at it in awe; unless you live at sea, they're an uncommon sight.

Maybe it's about time I did my own version of Shark Week...hmm...
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