Viperfish are one of the fiercest predators living in the deep ocean. They live in the deep ocean where it is so dark they are invisible to other fish when they are still in the water. Viperfish use photophores along their sides to help conceal their body from fish swimming beneath it. They attract their prey with a “fishing lure” on top of their head. They have a low basal metabolic rate so they can go for days without eating.
Pacific Viperfish NOAA
The most obvious difference between these fish and others that inhabit the deep are their large heads with fang-like teeth. The teeth are so large that the fish cannot close their mouth with their teeth inside. Instead the teeth curve over the outside of the fish’s head almost to their eyes when their mouths are closed. They have a hinged skull that can be rotated when they swallow very large prey they have impaled with their fang-like teeth.
These fish have a long dorsal spine that comes out of their head with a photophore on the tip. The photophore is a natural light. They turn the natural light on and off to attract their prey. It acts like a fishing lure while the viperfish hangs perfectly still in the water. Food is scarce in the deep and these fish can go for a period of time without attracting another fish to eat.
There are nine recognized species of viperfish. The fish migrate vertically during a 24-hour period looking for food. They feed during the day at depths of about 1500 meters (5000 feet) where almost no light penetrates the ocean water. They use the photopores along each side of their body to give off a faint light to fool their predators beneath them looking for food. As day turns to night they move upward looking for food where it is more plentiful at shallower depths up to 600 meters (2000 feet) beneath the surface of the ocean.
Sloane’s viperfish are the most common species found in the deep ocean. They are usually a silver-blue color with pale fins. Some Sloane’s viperfish have been caught that are green, silver and black colored. Viper fish grow to be about 30 centimeters (12 inches) long when mature. Very little is known about how long these viperfish live. Scientists estimate they can live between 30 and 40 years. Viper fish caught in nets and brought to the surface of the ocean live only a few hours before they die.
Viperfish are known to eat shrimp, squid, hermit crabs, anchovies, mackerel and other little fish. They swim at high speeds toward their prey impaling them with their sharp teeth. Other animals that eat viperfish include dragonfish, dolphins and sharks. They live primarily in tropical to temperate waters. They have been found living around Australia in the Pacific Ocean and Maine in the Atlantic Ocean.
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