Gulper Eel
Eurypharynx pelecanoides
Animal Type: Deep-sea fish
Habitat: Deep open ocean
Diet: Carnivore
Special Feature: Huge expandable mouth
Other Name: Pelican eel
About the Gulper Eel
The gulper eel is one of the strangest-looking animals of the deep ocean. It is also commonly called the pelican eel because of its enormous mouth, which resembles the expandable pouch of a pelican.
Despite its name, the gulper eel is not a true eel. It belongs to a separate group of deep-sea fishes that have evolved long, slender bodies and highly unusual jaws.
Most of its body is very thin, making the huge head and mouth look especially dramatic.
That Enormous Mouth
The gulper eel's most famous feature is its gigantic mouth. Its jaws are loosely connected and can open extremely wide.
A pouch-like throat beneath the mouth can also expand. This allows the gulper eel to capture prey that may appear surprisingly large compared with its narrow body.
The huge mouth is useful in the deep ocean because food can be difficult to find. When a meal appears, the gulper eel needs to make the most of the opportunity.
Gulper eels have a light-producing organ near the tip of their long tails. This organ can glow and may help attract prey or communicate in the darkness of the deep ocean.
The Midnight Zone
Gulper eels are commonly found in the Midnight Zone, also called the Bathypelagic Zone.
This zone stretches from about 1,000 to 4,000 meters (3,280 to 13,123 feet) beneath the ocean's surface.
No sunlight reaches these depths. The only natural flashes of visible light come from animals that produce their own light through bioluminescence.
Temperatures are cold, food is scarce, and water pressure is enormous. Deep-sea animals must be specially adapted to survive here.
What Do Gulper Eels Eat?
Gulper eels are predators that feed on small fish, crustaceans, squid, and other animals found in the deep ocean.
Their giant mouths allow them to engulf prey rather than relying on strong jaws or large teeth.
Although their mouths are enormous, their teeth are actually quite small.
A Long, Strange Body
Behind its oversized head, the gulper eel has an extremely long and narrow body.
Its body gradually tapers into a thin tail that can look almost whip-like. This makes the animal very different from the thicker-bodied eels commonly found near reefs and coastlines.
The lightweight body is well suited to the deep sea, where conserving energy is extremely important.
The Glowing Tail
At the end of the gulper eel's tail is a bioluminescent organ.
Bioluminescence is light produced by a living organism through chemical reactions inside its body.
Scientists believe the glowing tail may help attract prey toward the eel, though it may also serve other purposes in the dark ocean.
Can It Really Swallow Anything?
The gulper eel is sometimes described as being able to swallow animals larger than itself because of its enormous mouth.
Its expandable jaws certainly allow it to capture relatively large prey, but gulper eels often feed on much smaller animals such as crustaceans and small fishes.
The giant mouth may be especially useful for scooping up food when prey is scattered and difficult to find.
Life Under Extreme Pressure
The Midnight Zone is under tremendous water pressure. At these depths, pressure can be hundreds of times greater than it is at the surface.
Gulper eels and other deep-sea fish have flexible, soft bodies that are adapted to these conditions.
They do not have the same kinds of large gas-filled spaces that would cause problems for many surface-dwelling animals.
Swimming in the Deep
Gulper eels are not built for constant high-speed swimming.
Instead, their long bodies and tails allow them to move through deep water while using relatively little energy.
Conserving energy is especially important in the deep ocean because meals can be few and far between.
Where Are Gulper Eels Found?
Gulper eels have been found in deep ocean waters around the world.
They live far from sunlight in tropical and temperate regions of the Atlantic, Pacific, and Indian Oceans.
Because they spend their lives so far below the surface, humans rarely encounter living gulper eels without specialized deep-sea equipment.
Why Do Deep-Sea Animals Look So Strange?
Animals like the gulper eel can look bizarre when compared with fish living near the ocean surface.
But in the Midnight Zone, features such as huge mouths, expandable stomachs, glowing organs, dark coloration, and flexible bodies can be extremely useful.
The gulper eel's unusual appearance is the result of millions of years of adaptation to a world that is permanently dark, cold, pressurized, and short on food.