Sea creatures of Alabama: Rare pocket shark found in Gulf glows in the dark
Only two specimens have ever been collected of this shark, including one in the Gulf of Mexico.
Mason Reed 
Deep within the Gulf of Mexico resides a creature so compact it could fit in the palm of your hand—or a pocket. While the moniker might sound like something out of a fantasy novel, the pocket shark is very real, though you are unlikely to encounter one off the coast of Alabama or find much about it in a casual internet search.
A Creature of Mystery
Pocket sharks are among the rarest marine animals on Earth, with only two specimens ever documented. Greg Graeber, a marine educator at the Dauphin Island Sea Lab, notes that the creature defies conventional shark expectations: "It doesn’t even look like a shark," Graeber said. "It looks almost like a 'Pokemon' thing."
Measuring roughly five inches, these American pocket sharks are distinguished by mysterious pouches on their sides. Scientists are still investigating the purpose of these anatomical quirks, which sit beneath large, rounded heads and two small dorsal fins.
Glowing in the Deep
Perhaps the most fascinating trait of this elusive shark is its bioluminescence. Research from Tulane University indicates that these sharks possess the ability to glow in the dark by secreting a bioluminescent fluid, likely through their signature pouches. Because they inhabit such extreme deep-sea environments, their daily behaviors, feeding habits, and reproductive cycles remain largely unknown.
From the Gulf to the Record Books
The scientific history of the pocket shark is equally rare. The first specimen was discovered in 1979 in the Pacific Ocean off the coast of Chile and currently resides at the Zoological Museum in St. Petersburg, Russia. The second was accidentally recovered in 2010 during a research expedition by the NOAA ship Pisces in the Gulf of Mexico.
For years, the specimen sat forgotten in a freezer until researcher Mark Grace identified it in 2013. He facilitated its transfer to Tulane University to be housed in its Royal D. Suttkus Fish Collection. Following extensive study, researchers confirmed in 2019 that the Gulf find was a distinct species from the Chilean specimen, leading to its classification as the American Pocket Shark, as detailed in this research article.
The American version differs from its Pacific cousin by having fewer vertebrae and displaying specialized organs called photophores across its body to produce light. While all sharks share a cartilaginous skeleton, only 57 known species exhibit bioluminescence, according to the Ocean Conservancy.
Don't expect to spot one on your next beach trip or routine boat outing. However, Graeber notes that if you ever find yourself in the deep waters beyond the Continental Shelf, that small flicker of light you see in the darkness just might be a pocket shark.
