Giant-mouthed Pelican Eel: Predator of the Midnight Zone Swallowing Prey Larger Than Itself
Deep-Sea Predator: The Pelican Eel
The Pelican eel, scientifically known as Eurypharynx pelecanoides and also referred to as the Gulper eel, is a fascinating deep-sea creature known for its large, hinged jaw and expandable stomach. This species dwells in the tropical and temperate regions of the deep ocean, at depths ranging from 500 to 3,000 meters.
Using its narrow, whiplike tail and snakelike body, the Pelican eel navigates the dark abyss known as the "midnight zone." Despite its delicate appearance, the eel can consume substantial prey thanks to its unique feeding mechanism. As it opens its immense mouth, its elastic pouch, located under its lower jaw, balloons open, trapping anything unlucky enough to be nearby. Simultaneously, the eel's throat and stomach expand, allowing it to swallow prey significantly larger than itself.
One notable feature of the Pelican eel is its deep black skin, which absorbs nearly all light, making it virtually invisible in the dark depths of the ocean. Measuring about 1 meter long, the eel's lower jaw is approximately one-quarter the length of its entire body, with tiny eyes and very small teeth. The eel lacks scales and a swim bladder, hindering its swimming and hunting abilities.
To compensate for its poor swimming and hunting skills, the Pelican eel has developed an effective luring technique. A light organ, or photophore, located at the tip of its tail or a luminous organ (called an "esca") on a stalk near its chin, emits a pink or bright red glow in the dark water, potentially serving as a fishing lure that attracts prey close to its enormous, trap-like mouth.
In 2023, scientists exploring waters near Costa Rica observed a Pelican eel that had recently consumed a meal. As it swam away from the camera, its distended belly suggested that the eel's recent dinner was likely a squid.
As adult male Pelican eels mature, their jaws weaken and they lose teeth, but they develop larger olfactory organs, improving their sense of smell. Researchers believe this enhanced sense of smell aids in finding mates. However, more research is needed to understand the habits and behaviors of this elusive deep-sea dweller.
Subscribe to our daily newsletter to stay informed about the world's most intriguing discoveries.
The Pelican eel, thriving in the deep ocean, is an essential subject of environmental-science research due to its unique adaptations to its surroundings, such as its ability to consume weather-resilient prey like squids in the abyssal depths. The enlarged lower jaw of this species, a key feature in its survival, is a testament to the wonders of science and evolution.
