alligator-gar-fish ambush-predators animal aquarium aquatic atractosteus-spatula carnivores distinctive-snout elongated fish freshwater-fish gar habitat-destruction large largest-garfish piscivorous predator-fish primarily-piscivores primitive-fish river river-fish riverine Singapore Southern-United-States stalking-predators torpedo-shaped unusual voracious water zoo 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 protuberance reptile reptilian teeth vocal-resonator