Researchers studying the feeding habits of sperm whales ended up finding more than they could have expected when they came across on the second ever known specimen of an incredibly rare and very small shark dubbed the "Pocket Shark."  The first pocket shark was discovered 36 years ago near Peru but hasn't been seen since.

The specimen appears to be a juvenile male and, at just over 5 inches long, could definitely fit inside your pocket.  However, that's not how it got its name.  Researchers nicknamed Mollisquama parini the "pocket shark" not because it is small enough to fit in your pocket, but because of its "remarkable pocket gland," found just above the pectoral fin.

Scientists are still baffled by what this pocket is actually for, but they have guessed that it could be instrumental to the production or the excretion of pheromones.

The only other pocket shark that has ever been seen by humans was an adult female that measured a little over 15 inches in length.

Mark Grace, the study's lead author, said in a statement that the new specimen was very young, young enough to have an unhealed umbilical scar. He was collected off the coast of Louisiana, which, Grace notes "has us thinking about where mom and dad may be, and how they got to the gulf," adding, "The only other known specimen was found very far away."

This latest specimen was accidentally collected in 2010 as part of a study examining the feeding habits of sperm whales.  The shark was already dead when first examined before freezing, about a half hour after the catch, according to the study.

Years later Grace found the specimen among the frozen catch collected from the NOAA study.

The discovery of a second specimen is exciting in the scientific community as researchers simply don't know very much about the pocket shark.  There is little doubt that scientists cannot wait to get a closer look at this specimen as they try to learn more about how and where it lives and how it eats.

The tiny fish known as the Pocket Shark is a member of the family Dalatiidae.  This means that it could engage in a characteristic feeding method of the closely related "cookie cutter" shark. 

"Sharks of the genus Isistius (cookie cutter sharks) employ a unique feeding behavior that allows them to use their cookie-cutter-like teeth to excise a nearly symmetrical oval flesh plug from a variety of prey species including marine mammals, tunas, billfishes, and squids," the study explains.