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 a complete breastband. semipalmated plovers are larger, thicker-billed, and has a pale collar. Ironically, it is the "lack" of a pale collar which gives the collared plover its English language and scientific names. The collared plover is found on sandy coasts, estuarine mud, inland riverbanks and open sandy savannas. It breeds from Mexico south through Central America and most of South America. It also occurs on some of the southern Caribbean islands, and both Trinidad and Tobago. It appears to be mainly sedentary, although there is some evidence for limited seasonal movements. Collared plovers feed on insects and other invertebrates,