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
Collared plover flight feathers are dark with a white wing bar, and the tail shows white sides. The female collared plover is usually very similar to the male, but some individuals can be sexed by a brown tinge to the black areas. Immature birds lack any black on the head, and the breast band is replaced by brown patches on each side of the chest. The flight call is a sharp metallic "pip". Two sympatric "Charadrius" species are very similar: The snowy plover is similar in size and structure to this species, but is paler above, has dark legs, and never has