Most of us are familiar with eels that are snake-like fish with elongated bodies. There are different types of eels that are found in both freshwater as well as seawater. The gulper eel is an eel-like fish that is usually found in deep seas. It is not a true eel and is not related to the order of true eels, Anguilliformes. Gulper eels belong to the order Saccopharyngiformes and family Eurypharyngidae. In fact, the gulper eel (Eurypharynx pelecanoides) is the single member of the genus Eurypharynx.
Gulper eels are deep-sea creatures that are found in tropical and temperate oceans. These fish are usually found at a depth of around 3000 to 26,200 feet. Occasionally, they travel to the surface and may sometimes shift to rivers; as they find it difficult to locate food in their natural habitat. Gulper eels resemble true eels in looks, as they have a snake-like body structure. Unlike true eels, they have long and thin tails, which help them in locomotion. In fact, the tail of the gulper eel is so long that, it sometimes gets knotted. Gulper eels have almost no pectoral fins and are blackish or dark green in color. The characteristic feature of the fish is its loosely hinged mouth, which is very big and wide. This enormous mouth is bigger in proportion to its body. The lower jaw has a big pouch-like structure, where prey can be deposited. It is due to this pouch-like structure that this fish is also called pelican eel. It is also known as umbrella mouth gulper, and even this name is derived from their giant mouth. The following are some of the amazing umbrella mouth gulper eel facts.
- They have big mouths that are wide enough to swallow large prey. In fact, the length of the jaws is almost one-fourth of their body length.
- Even the stomach of the gulper eel is stretchable, and can hold large amount of food. However, this fish feeds on small crustaceans, in spite of having a big mouth and a stretchable stomach.
- Even though, gulper eels have big mouths, their teeth are small; and this indicates that they are not intended to prey upon large animals. Apart from crustaceans, gulper eel diet includes fish, seaweed, cephalopods such as squids and octopus, etc.
- The mouth of the fish acts like a net, as it swims into large groups of small fish and shrimp. Their wide open mouth fills with food as well as water. The water is slowly released through the gill slits.
- Even the eyes of this deep-sea creature are too small. Expert opinion is that their eyes are meant for detection of lights rather than formation of images.
- This fish has a tiny light-producing organ at the tip of its tail. This organ called photophore, has numerous tentacles, and glows pink, through bioluminescence.
- This light-producing organ can also produce red flashes, occasionally. These red flashes are used to attract prey, as they keep their tail tip near their wide open mouths; so that they can swallow fish and other organisms that move towards the light source.
- It is said that mature males have bigger eyes and olfactory organs; as compared to females, who do not change much, as they become sexually mature. It is with the help of these olfactory organs that males sense the pheromones released by the females. It is also said that after reproduction, gulper eels die.
As of now, very little is known about gulper eels; that are difficult to locate, as they live in deep seas.