Crocodile longevity is not well established, but larger species like the Nile crocodile live longer, and may have a potential average life span of 70 to 100 years, though no crocodilian species commonly exceeds a lifespan of 50 to 60 years in captivity. Natural mortality of young Nile crocodiles An estimated 10% of eggs will survive to hatch and a mere 1% of young that hatch will successfully reach adulthood. The full range of causes for mortality of young Nile crocodiles is not well understood, as very young and small Nile crocodiles or well-concealed nests are only sporadically observed. Unseasonable flooding (during nesting which corresponds with the regional dry season) is not uncommon and has probably destroyed several nests, although statistical likelihood of such an event is not known. The only aspect of mortality in this age range that is well studied is predation and this is most likely the primary cause of death while the saurians are still diminutive. The single most virulent predator of nests is almost certainly the Nile monitor. This predator can destroy about 50% of studied Nile crocodile eggs on its own, often being successful (as are other nest predators) in light of the trance-like state that the mother crocodile enters while brooding or taking advantage of moments where she is distracted or needs to leave the nest. In comparison, perenties (Varanus giganteus) (the Australian ecological equivalent of the Nile monitor) succeeds in depredating about 90% of freshwater crocodile (Crocodylus johnsoni) eggs and about 25% of saltwater crocodile nests. Mammalian predators can take nearly as heavy of a toll, especially large mongooses such the Egyptian mongoose (Herpestes ichneumon) in the north and the water mongoose in the south of crocodile's range. Opportunistic mammals who attack Nile crocodile nests have included wild pigs, medium-sized wild cats and baboon troops. Like Nile monitors, mammalian predators probably locate crocodile nests by scent as the padded-down mound is easy to miss visually. Marabou storks sometimes follow monitors to pirate crocodile eggs for themselves to consume, although can also dig out nests on their own with their massive, awl-like bills if they can visually discern the nest mound. Predators of Nile crocodiles eggs have ranged from insects such as the red flour beetle (Tribolium castaneum) to predators as large and formidable as spotted hyenas (Crocuta crocuta). Unsurprisingly, once exposed to the elements as hatchlings, the young, small Nile crocodiles are