The Ambulaquasaurus, Ambulaquasaurus cristarufus, is a specialized, fish-hunting dromaeosaur that wades in the rivers of Skull Island. It measures 10-14 feet long.

A dedicated fish-eater, Ambulaquasaurus is a slender dromaeosaur closely related to Venatosaurus. With long limbs and an elongated, needle-toothed snout, the predator is ideally suited to life as a fisher.

Specialized eyes minimize the effect of glare on the water. Cunningly, they choose hunting spots that are shaded by cliffs or overhanging vegetation to further cut down reflections that might impede their ability to spot fish below the surface. Adapted to pin slippery, fast-moving fish, the jaws are similar to the gharial crocodilian of Asia. Even fish almost three feet long are no match for the bite of Ambulaquasaurus, with its lightning reflexes and eyesight every bit as keen as the edge on its teeth.

One of the largest of the wading dinosaurs, Ambulaquasaurus are strong enough to be able to wade deep into fast-moving water to snap up prey that other fishers are either too small to subdue or find it too difficult to reach. They hunt throughout the island, from the coastal marsh, up the fast-flowing rivers, and into the tiny tributary streams. A particular specialty of the species is waiting next to rapids to snap up the Skull Island freshwater mullet species, the sparkleside, as they make their way up and down the river. Living in the estuary most of the year, sparklesides spawn in inland pools, forcing them to make the perilous journey upstream and back every breeding season. Ambulaquasaurus time their arrival at the rapids to be ready and waiting when the first sparkleside heads upriver, each individual taking up position in a traditional spot. Displays and growls are usually enough to sort out issues of dominance and fights over prime fishing sites quickly, permitting all concerned to concentrate on the business of catching prey.