Pelican eel (Eurypharynx pelecanoides)
The pelican eel’s most notable feature is its enormous mouth, much larger than its body. The mouth is loosely-hinged, and can be opened wide enough to swallow a fish much larger than the eel itself. The pouch-like lower jaw resembles that of a pelican, hence its name. The stomach can stretch and expand to accommodate large meals, although analysis of stomach contents suggests that the eels primarily eat small crustaceans. Despite the great size of the jaws, which occupy about a quarter of the animal’s total length, it has only tiny teeth, which also would not be consistent with a regular diet of large fish.