Freshwater rivers, streams, swamps in Malaysian rainforests; territorial.
Near-black coloration blends with dark water/vegetation. Sit-and-wait or slow-stalk hunting.
Fish, amphibians, reptiles, birds, small mammals, carrion.
Solitary except breeding season. Vocalizations (hiss, grunt, roar) + body language. Females build mound nests; both parents may guard hatchlings.
Primarily nocturnal.
IUCN Vulnerable—habitat loss, hunting, pet trade. Protection efforts underway.