The viper dogfish, also scientifically named Trigonognathus kabeyai, is a part of the Etmopteridae family of the Chondrichthyes classification. Their scientific name Trigonognathus is two Greek words “trigonon” and “gnathus,” which describes their triangular jaw. The second part, kabeyai, is named after the captain of the boat which discovered them, Hiromichi Kabeya. The species is found throughout the Pacific Ocean, from Japan to Hawaii.
It’s believed that the viper dogfish originated more than 40 million years ago in the Middle Eocene. One of the dogfish’s more interesting features is that it seems to be missing a specific muscle that’s responsible for pulling the jaws forward when going after prey. Instead of using this muscle, the fish uses what is known as a hyomandibular bone. This unique bone which swings down and forward to compensate. This ends up working better for the viper dogfish as they become capable of moving their jaws both vertically and horizontally.
Appearance
The viper dogfish is a strange-looking shark with a flattened head and a slender, cylindrical body. Small, rounded snouts are characteristic of these animals as are long, narrowly triangular jaws, unique-looking round eyes, and spike-like spiracles. They have a distinctive tooth structure with teeth spaced fairly far away from one another and all of which look like fangs. The upper and lower symphyses each have 6-10 upper teeth and 7-10 lower teeth. Their gills are divided into five pairs, one set of which is bigger than the other four.
Viper dogfish have quite small fins. This includes their rounded pectoral fins and two dorsal fins. The first and second dorsal spines have grooved features that make them stand out. A design that makes it a unique sea dweller. Its skin, excluding its fins, is densely covered with seemingly randomly shaped and placed denticles.
The longest male specimen grew to 19 inches and the longest female was a few inches long, ranking in at 21 inches in length. These two specimen were also 0.95 lbs and 1.7 lbs respectively.
Credit: Stephen M Kajiura
Habitat
The viper dogfish is a species of shark that has only been seen in certain parts of the Pacific near the Kii Peninsula along the coasts of Japan and Taiwan. Specimens have also been sightings near one of the smallest Hawaiian Islands. The viper dogfish has primarily been seen off of the Kii Peninsula in Japan but has also been extracted from the stomachs of other fish found in various locations.
The viper dogfish is a unique species that migrate between large distances in 24 hours. While they spend most of their days between 890 and 1,180 feet deep along the upper continental slopes and seamounts, they come up to 490 feet deep during the cold of the night. The first viper dogfish were caught in 1986 off the southern coast of Japan, Cape Shiono. It was two immature males that measured 22 cm long. It was found at the depth of 330 m.
Diet
The viper dogfish is a carnivorous hunter with a taste for crustacean-like creatures. But unlike many other sharks, its diet focuses on smaller prey such as bony fishes and lanternfish. This species is marvelously adapted to its harsh environment. The creature uses its unique jaw and teeth to reach out and grasp rather than cut, unlike other types of dogfish sharks. They extend their jaws in order to swallow their prey. Due to the shape of their jaw and method of eating, they can consume prey that’s nearly as large as they are but they are incapable of biting.
Reproduction
The viper dogfish is a scarce species that has only been recorded a handful of times by researchers. Found in areas of the deep sea around the world, this shark is one of the most peculiar species in the ocean due to its unique reproductive habits. Like many deep water animals, because they are rarely seen near the surface of the water, scientists don’t have too much information about their reproductive habits. But it is known that instead of laying eggs like most other sharks do; the viper shark has live babies, with litters of up to two dozen pups recorded.
Threats
The viper dogfish’s natural predators are the bigeye tuna and the sickle pomfret, with a handful of other, bigger deep-sea fish. The total number of viper dogfish in the world is unknown, even though they are not considered in danger or near-extinct. Since the species is rarely caught or seen, official numbers have yet to be recorded. However, they are considered “Least Concern” by the IUCN, and there are no real conservation measures in place.
Facts about the Viper Dogfish
- Researchers believe an average pregnancy of a viper dogfish can last between 1.5 and 2 years.
- This species of dogfish is viviparous, which means they give birth to living offspring. They do this by internally creating yolk to preserve the offspring.
- The largest known male to be caught is 47 cm, and the largest female is 54 cm long.
- The viper dogfish is believed to originated around 41 million years ago. Fossilized teeth have been found in southwestern France and northeastern Venezuela.
FAQs
Where do viper dogfish inhabit?
The viper dogfish are known to only inhabit the Pacific Ocean near Japan, the Bonin Islands, near some regions of the Hawaiian Islands. Since they usually spend their day at 300 meters, there haven’t been a lot of sightings.
What do viper dogfish eat?
They mainly eat bony fish, lanternfish, and crustaceans. They can eat prey that’s almost half their size due to the construction of their jaw and teeth.
Is the viper dogfish a shark?
Yes. the viper dogfish is unique species of dogfish shark that is considered a deep-sea animal. It contrasts biologically with its cousins, the dogfish shark.
Do dogfish sharks have venom?
Unlike most sharks, dogfish do have venom. They have small spines on the front of their dorsal fins that produce a non-toxic venom.
Can dogfish hurt you?
Dogfish are not known for hurting human beings. But they do have venomous spines on the front of each dorsal fin that you should be careful of if you encounter one.
Do dogfish have sharp teeth?
Yes, dogfish have sharp teeth. They are often described as fang-like and can appear quite intimidating. But, the animal is so small that their teeth pose little threat.
