Nile crocodile stability and additional weight to sink in water, this bearing great probability over the theories that they assist in digestion and staving off hunger. However, Alderton (1998) stated that a study using radiology found that gastroliths were seen to internally aid the grinding of food during digestion for a small Nile crocodile. Herodotus claimed that Nile crocodiles have a symbiotic relationship with certain birds, such as the Egyptian plover ("Pluvianus aegyptius"), which enter the crocodile's mouth and pick leeches feeding on the crocodile's blood, but no evidence of this interaction actually occurring in any crocodile species has been found, and
Symbiotic binary term "symbiotic variable" or "symbiotic variable star" is sometimes also used synonymously, but more commonly is used only for Z Andromedae variable stars. Symbiotic binaries are often divided into two sub-types based on the nature of the continuum in their spectra. "S-type" systems have a stellar continuum since the giant component is not obscured. "D-type" systems are surrounded by optically thick dusty nebulosity and the star itself is not directly visible. D-type systems tend to contain a Mira variable or other long period variable star. Some symbiotic stars have jets which are a collimated outflow of material. These typically are