animal aquarium aquatic bulbous bulbous-growth carnivore carnivorous critically-endangered crocodile crocodilian elongated-snout fish-eating-crocodile freshwater gavial gavialis-gangeticus ghara Gharial hollow-bulbous-nasal-protuberance Indian-gavial Indian-gharial interdigitated-teeth jaws long-narrow-snout long-nosed-crocodile nostril-swelling piscivorous protuberance reptile reptilian Singapore teeth vocal-resonator water zoo alligator-gar-fish ambush-predators atractosteus-spatula carnivores distinctive-snout elongated fish freshwater-fish gar habitat-destruction large largest-garfish predator-fish primarily-piscivores primitive-fish river river-fish riverine Southern-United-States stalking-predators torpedo-shaped unusual voracious