“Pygmy sharks underbelly glows to attract prey that swims beneath it.”

The Pygmy shark is the second smallest shark in the world behind the dwarf lantern shark. Their average length measures 11 inches, roughly the size of a 2L soda bottle.

They are black with white tips on the edges of their fins, and their underbellies have a luminous glow. They prefer living in deep water at depths of 6,500 feet. But, they migrate up to around 650 feet to hunt at night. Because they are so small and live in deep water, they are not a threat to humans.

Pygmy Shark Facts

• Pygmy sharks are tiny and only grow up to a maximum length of 11 inches
• They prefer temperate and oceanic areas in the South Indian, South Atlantic, and Pacific Oceans
• Pygmy sharks are ovoviviparous and give birth to around eight pups per litter
• Once thought to be the smallest shark in the ocean, only to be overtaken by the dwarf lantern shark.
• The pygmy shark has a unique characteristic to help catch its prey: a glowing underbelly.

Pygmy Shark Scientific Name

The Pygmy shark’s scientific name is Euprotomicrus bispinatus, and it belongs to the Family Dalatiidae and falls under the Class Chondrichthyes. The IUCN lists them as Least Concern.

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There are seven subspecies that all have their own unique characteristics, which include:

Kitefin Shark

The kitefin shark is a medium-sized shark with a cylindrical body, a short, blunt snout, and densely thick fringed lips.

The first spineless dorsal fin is situated behind the pectoral fin rear tips. However, the second dorsal fin is more predominant. The ventral caudal-fin lobe is very weak, and the majority of the fin is translucent.

Adults can grow up to 6 ft long and weigh up to 18 pounds. They have a large variety in their diets and eat:

• Small deep water fish
• Skate fish
• Small sharks
• Squids
• Octopus
• Shrimps
• Lobsters
• Woodlouse
• Amphipods
• Siphonophores
• Polychaetes

Kitefin sharks are found in the Atlantic, Pacific, and Indian Oceans and hover above the sea floor due to their oil-filled liver that provides natural buoyancy. In addition, they are solitary hunters.

Taillight Shark

While scientists know little about the taillight shark, they examined four specimens. The first was a juvenile female measuring 6.9 inches long. The second was a mature male measuring 1.4 feet; the third was a mature male 1.5 feet long. Lastly, the fourth was an adult female measuring 1.7 feet long.

The taillight shark is covered in non-overlapping dermal denticles, and its snout is rounded, long, and bulbous with big oval eyes.

They have a pouch on their bellies filled with a glowing blue fluid. Researchers don’t know much about the function of the fluid; however, there are theories.

One theory believes that the fluid is used in the darkness to confuse predators or attract prey, similar to the octopus. Another possibility is the glowing fluid attracts mates.

Longnose Pygmy Shark

The longnose pygmy shark is dark brown with lighter tips on the edges of the fins. Their two dorsal fins (the first being more prominent than the one closer to the rear) don’t have frontal spins like many other shark species, and there is no anal fin.

The body is covered in dermal denticles with wedge-shaped crowns, and mature adults can grow up to 11 inches long. Longnose pygmy sharks feed on invertebrates and pelagic fish.

They don’t have a wide distribution and are found near Ascension island in the Soth Atlantic Ocean and off the coast of Durban, South Africa, in the southwestern Indian Ocean.

Cookiecutter Shark

The cookiecutter shark feeds off larger fish without killing them, making it a parasite. It uses its sharp, pointy teeth to latch onto larger prey like:

• Bony fish
• Sharks
• Marine mammals

On its lower jaw sits thick, sturdy, triangular teeth, which help the cookiecutter bite out a chunk of flesh. Although this shark lives in deep waters, there has been one recorded incident where it has harmed a human.

The person in question was an athlete swimming long distance between Hawaii’s islands during the evening. During his swim, boats surrounded him with lights that attracted prey.

The cookiecutter bit him on the calf, leaving him with a nasty scar, but luckily, there was no permanent harm done.

Pocket Shark

The pocket shark’s most fascinating feature is the presence of a hidden pocket gland situated just above each pectoral fin.

Some scientists believe these glands emit pheromones to attract a potential mate. However, it is more likely that the glands produce a glowing liquid that pocket sharks use to distract and confuse predators or attract prey in the dark waters they inhabit.

The pocket shark only measures 5.5 inches in length, and its body forms a shape like a cigar. However, unlike most sharks with a pointy snout, they have rounded heads.

Smalleye Pygmy Shark

The smalleye pygmy shark is a brownish-black color with lighter fin margins and a glowing underbelly. Its diet consists of:

• Squid
• Krill
• Shrimp
• Small boney fish

They are viviparous, meaning the eggs are fertilized and hatch within the uterus, and the mother gives birth to live pups. The males reach sexual maturity at 5.9 inches long. However, when fully grown, they can reach lengths of just 8.6 inches.

The smalleye pygmy inhabits a wide variety of locations, and small patches occur in Japan, the Philippines, and northern and eastern Australia.

Spined Pygmy Shark

Spined pygmy sharks are a brownish-black color with light tips on the edge of their fins. Like many of its cousins, they have a glowing underbelly. They enjoy eating bony fish and squid and will follow their prey during vertical migrations.

The spined pygmy is viviparous, meaning the embryos develop by receiving nutrients through a yolk and hatch in the uterus before birth. So while the adult females contain 12 eggs, the litter size is much less.

Pups measure 3.5-3.9 inches when born, and the males reach sexual maturity at 5.9 inches long. However, the females must wait until they are 6.6 to 7.8 inches long.

They occur across the Eastern Atlantic (just off the French and Madeiran coastlines), Western Atlantic (Bermuda, southern Brazil, and Northern Argentina), Western Indian Ocean (Somalia),  western Pacific (Phillippines, Taiwan, and Japan), and Australia.

Pygmy Shark Appearance

The pygmy shark is black in color and has light edges on its fins. Its body is cylindrical, and it has a bulbous snout with big eyes.

To make this little creature stand out, it has luminous organs along the underbelly that make it glow. The function of the glow is unknown. However, it is likely used to confuse predators or attract prey. There are many theories about its function, and they include:

• Prey swimming beneath the pygmy shark might be attracted to the glow and swim closer
• Camouflage from predators because the glow merges with the light from the upper surface, making them harder to see
• It’s believed this glow emits pheromones to attract a mate

The pygmy shark is the second smallest shark on the planet and has two dorsal fins—the caudal fin, shaped like a paddle with almost identical lower and upper lobes.

The females reach lengths between 8.6 to 10 inches, while the males are smaller and only measure 8.6 to 8.7 inches.

Pygmy Shark Behavior

Not much is known about their behavior except they are mostly solitary. However, they do occur in groups, especially when migrating vertically to find food.

Pygmy Shark Habitat

Pygmy sharks live close to the ocean floor at depths of 6,500 feet during the day. However, their preferred prey rises to the surface to feed on plankton at night, so pygmy sharks follow them to depths of around 650 feet.

Pygmy Shark Diet

The pygmy likes to eat:

• Deepwater squid
• Bony Fish
• Crustaceans

Pygmy Shark Predators and Threats

Pygmy sharks have no recorded threats or predators. Because it is so tiny, it can avoid getting caught in fishermen’s nets. However, there are cases where people catch them accidentally. Unfortunately, researchers require more information on whether overfishing is affecting their population. 

Pygmy Shark Reproduction, Babies, and Lifespan

These sharks are ovoviviparous and develop eggs inside the uterus where they hatch. The pygmy shark gives birth to live young with an estimated litter size of eight pups.

Pups measure 2.3 to 3.9 inches at birth and reach sexual maturity at 8.6 to 9 inches long. However, pygmy sharks are fully grown when they reach 11 inches.

Pygmy Shark Population

Unfortunately, no data is available on structure, population size, or trends for the pygmy shark.

Pygmy Shark In the Aquarium

There are no aquariums that house the pygmy shark.

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