The mere mention of sharks may evoke a shudder in many, but I’m sure even serious galeophobes won’t get sweaty palms looking at this endearing little fish. This is a pocket shark, and alongside being utterly adorable, it’s also extremely rare: only two have ever been found. Although our knowledge of this elusive animal is extremely limited, scientists have just published a detailed description of the second specimen discovered, which reveals some interesting facts about this unusual vertebrate.
As described in Zootaxa, the shark was not actually found swimming in the sea, but rather in a collection of specimens held at one of the NOAA’s laboratories. The animal was collected back in 2010 around 190 miles offshore of Louisiana during an NOAA expedition to study sperm whale feeding behaviors. Although the shark was photographed at the time, it spent the next three years in a freezer, waiting for NOAA fisheries biologist Mark Grace to painstakingly make his way through bags and bags of frozen specimens before finally coming across it.
While Grace wasn’t sure what it was, it immediately captured his attention as never before had he seen anything like it: The teeny, 5.5-inch (14 cm) baby male had a pair of bizarre orifices over its pectoral fins. After a thorough examination of the shark’s features, the researchers took a tissue sample for genetic analysis, which revealed their suspicions were correct: it belonged to the genus Mollisquama, making it the second pocket shark discovered so far. These are a type of sleeper shark within the family Dalatiidae, which also includes the kitefin and cookie cutter species. Like these relatives, the researchers believe that pocket sharks may feed by taking an oval-shaped chunk out of the flesh of prey species, such as large fishes or squid.
Although the purpose of the shark’s unique pocket remains uncertain, scientists have suggested that it may function to produce and release pheromones to attract mates. Another interesting feature that was not noted in descriptions of the first specimen was a collection of light-emitting organs called photophores on its abdomen, but photographs alone are insufficient to deduce whether the scientists missed these on the first animal or if they were indeed absent.
Something else that has puzzled scientists is the fact that the habitats in which the two specimens were recovered are considerably different. The first pocket shark, a female measuring almost half a meter (17 inches) in length, was found in cold waters off the coast of Peru, but this one was found in much warmer waters in the Gulf of Mexico.
“Discovering him has us thinking about where mom and dad may be, and how they got to the Gulf,” Grace said in a statement. “This record of such an unusual and extremely rare fish is exciting, but it’s also an important reminder that we still have much to learn about the species that inhabit our oceans.”