The Basilisk lizard (Basiliscus) is a reptile native to the rainforests of Central and South America. It is known for its extraordinary ability to sprint across the surface of water, earning it the nickname, the “Jesus Christ Lizard.” This unique locomotion is primarily a survival mechanism, allowing the lizard to escape predators in its semi-aquatic habitat.
Identification and Natural Habitat
Basilisk lizards are medium-sized reptiles. The common basilisk (Basiliscus basiliscus) measures up to two and a half feet in total length, with the long, whip-like tail accounting for up to 70% of that size. Males are larger than females and possess prominent, sail-like crests on their head, back, and tail. Their coloration ranges from bright green and olive to brown, often featuring darker cross bands and light stripes, which provides excellent natural camouflage.
These lizards thrive in tropical rainforests, found from southern Mexico south to Ecuador and Colombia. They are semi-arboreal, spending much of their time in trees and dense vegetation, but they are never far from water. Basilisks prefer habitats near rivers, streams, and ponds at lower elevations.
The Science of Running on Water
The basilisk’s ability to run across water is a feat of biomechanics, not surface tension, made possible by specialized adaptations on its hind feet. The long toes are equipped with a fringe of skin and scales that unfurl during a sprint, significantly increasing the surface area. This bipedal locomotion involves a rapid, cyclical three-step movement for each stride: the slap, the stroke, and the recovery.
The process begins with the slap phase, where the foot slams down onto the water surface at high speed, trapping a small pocket of air beneath it. This initial impact generates an upward force that supports a portion of the lizard’s weight. Next is the stroke phase, where the foot is pushed downward and backward through the water, creating a temporary air-filled cavity that acts like a piston to provide the main propulsive force.
The lizard executes the recovery phase by rapidly pulling its foot upward and out of the water before the air cavity collapses. This swift withdrawal minimizes drag and allows the lizard to prepare for the next step. Smaller and lighter individuals are the most successful, capable of sprinting 10 to 20 meters across the surface before they must resort to swimming.
Diet and Behavioral Adaptations
Basilisk lizards are omnivorous, and their diet changes as they mature. Juveniles are highly insectivorous, feeding on insects like crickets, spiders, and ants. Adults consume a more varied diet, including small vertebrates such as fish and smaller lizards, along with plant matter like fruits and flowers. This opportunistic feeding strategy is suited to their active, diurnal lifestyle.
The basilisk is highly agile and uses its brown or green-olive coloring to blend into the surrounding vegetation when resting. When threatened, its first instinct is to flee, often by dropping from a tree branch and sprinting toward or across the nearest water source. If capture is unavoidable, the basilisk can remain submerged underwater for up to 30 minutes.