Crocodile bulks of swallowed prey flesh and bone. Many large crocodilians swallow stones (called gastroliths or stomach stones), which may act as ballast to balance their bodies or assist in crushing food, similar to grit ingested by birds. Herodotus claimed that Nile crocodiles had a symbiotic relationship with certain birds, such as the Egyptian plover, which enter the crocodile's mouth and pick leeches feeding on the crocodile's blood; with no evidence of this interaction actually occurring in any crocodile species, it is most likely mythical or allegorical fiction. Since they feed by grabbing and holding onto their prey, they have evolved
Three-banded plover in flight, the exception being the closely related Forbes's plover that replaces it in west Africa. The adult three-banded plover has medium brown upperparts, and the underparts are white except for the two black breast bands, separated by a white band, which give this species its common and scientific names. The head is strikingly patterned, with a black crown, white supercilia extending from the white forehead to meet on the back of the neck, and a grey face becoming brown on the neck. The eye ring and the base of the otherwise black bill are red. The Madagascan subspecies "C.