False Catshark (Pseudotriakis microdon)

As you’ve probably noticed if you follow this blog regularly, many animals have names that make no sense at all. There are some rare species, however, that have names that are perfectly logical, and today’s animal is one of those.

When the first specimen was found, it was thought to resemble a catshark, but was subtly different enough to be placed in its own genus. Thus the name ‘false catshark’ (Pseudotriakis) was born. False catsharks are found in many places around the world, particularly around continental slopes. They live at depths of 500-1400 m, generally sticking near the ocean floor.

These sharks can get pretty big, growing to lengths of three meters. They are brown or grey in colour, which probably helps them blend into the seafloor. False catsharks have long, bulky bodies, and giant mouths. The insides of their mouths are filled with two hundred rows of teeth, but luckily these teeth are very small. Here’s where the logicalness of false cat sharks’ names get even better — the second part of its scientific name, microdon, means ‘small tooth’. I love it when things make sense!

Pseudotriakis_microdon_1

As a deep water species, getting pictures of live false catsharks is pretty rare. This one is pretty cool! Image credit: NOAA Ocean Explorer via Wikipedia

False catsharks are very lazy animals. In fact, their bodies aren’t really built for much action — their fins and muscles are soft and flabby. The catsharks get around this by having a very large and very oily liver. This organ can make up to a quarter of a catshark’s total bodyweight, and helps with the sharks’ buoyancy. With the aid of their livers, false catsharks can float near the bottom of the ocean without expending much energy. When they do hunt, the catsharks do actually move quickly. They prey mainly on other fish, squids, and octopi. The catsharks’ big mouths mean they can eat quite large prey.

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A picture of a false catshark showing its distinctive long dorsal fin. Image credit: CSIRO National Fish Collection via Wikipedia

Another unusual thing about false catsharks is their reproductive habits. Developing eggs feed on the yolk from their eggs, but switch to consuming ovulated eggs later in gestation. The mothers give birth to live young, usually only birthing two pups at a time. This type of reproduction is not unheard of in sharks, but is rare for ground shark species.

Though false catsharks may not be actual catsharks, I would argue they are much cooler than their namesakes. Of course, I don’t really know much about catsharks, having only written about one of them (the chain catshark). I guess there will have to be a future post on true catsharks, and then I can make an informed decision about which is better!

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