The Pygmy Shark (Euprotomicrus bispinatus) is a very small dwarf shark species ( the second smallest after the Dwarf Lantern Shark). It is a squaliform, kitefin shark from the family Dalatiidae, and the sole member of the Genus Euprotomicrus. It’s length is about 25cm (10 inches) in females and 22cm (8.7 inches) in males. Read on to find out more about the appearance, biology, habitat and more about this tiny shark.
Pygmy Shark Description
The Pygmy Shark is a cylindrical, dwarf shark with a bulbous snout, large eyes and shining organs at the underside of its body. It has a black upper body with a lighter colour on the edges of its’ fins. One of the most fascinating aspects of the Pygmy Shark is it’s luminous organs along the lower part of its’ body, meaning it glows in the dark.
Its tiny gills are slit open and it has a lower lateral keel on its caudal peduncle. It is one of the smallest sharks ever found in the sea. Like most larger sharks, the Pygmy has two small dorsal fins and a paddle-shaped caudal fin consisting of almost identical lower and upper lobes.
When they reach maturity, the female will be between 22-25cm (8.6 – 10 inches) and the males will grow to a smaller size at around 17 – 22cm (6.6 – 8.7 inches). The Pygmy Sharks diet consists of smaller sea creatures such as bony fish, squid and crustaceans.
The Pygmy Shark Habitat & Distribution
The Pygmy Shark is an oceanic species of the epipelagic, mesopelagic and bathypelagic that lives from the surface to more than 1500 metre below sea level. As a bioluminescent vertical migrator, it sinks down to the bottom during the day and ventures up closer to the surface at night. It can be found at 6,500 feet (2,000 meters) throughout the day and at approximate depths of 650 feet (200 meters) at night. This allows the Pygmy to take better advantage of the hunting grounds.
There are several theories as to how the Pygmy Shark uses its glowing belly. It is most likely attractive to smaller prey that swim underneath it, the smaller fish comes close to the glow allowing the Pygmies to attack quickly. Another advantage of the luminescence is that it can provide camouflage from predators above them at night. From below the glow merges with the light from the upper surface, making them less visible to predators. Clever little things!
You may think that the Pygmy Shark is a threatened species due to its small size, but in fact it is one of the few that are not in danger. Pygmies may be small, but it has a couple of tricks up its sleeves (including its luminous organs) to avoid the jaws of larger predators. Pygmies are believed to be abundant but people rarely see them due to the depths in which they dwell.
This fact has left the Pygmy in the shark world a mystery since it poses no threat to humans and is not commercially fished for its tiny meat fillets. The researchers did not devote much time to studying this species, so little is known about them. However, there are currently no specific conservation measures for this species as there is no concern for their population levels.
The Pygmy Shark is Ovoviviparous and gives birth to up to eight cubs in one litter, each at a length of around 6-10cm each.