Reptiles
Common Basilisk
Basiliscus basiliscus · also called Jesus Christ lizard, South American Jesus lizard, lagarto de Jesus Cristo
The common basilisk is the lizard that appears to walk on water. Startled off a riverbank, it rears onto its hind legs and sprints across the surface of the stream, and for a moment — especially if it is young and light — it seems to defy the water entirely. This is the original Jesus Christ lizard.
Overview
Basiliscus basiliscus lives in lowland forest from Nicaragua to western Colombia, always near water. Males reach about 70–80 cm, most of it tail, and carry tall crests on the head, back, and tail. Females are plainer and smaller. The diet is broad: insects, small vertebrates, freshwater shrimp and fish, plus flowers and fruit.
Running on water
A frightened basilisk drops to two legs and slaps its feet flat onto the surface, each foot pushing water down and creating a brief air pocket, then pulling up before that pocket collapses. Fringed toes spread on the downstroke to catch more water. Light juveniles can cross 10–20 m; heavy adults get a metre or two before sinking to a swim.
Plan B: dive
If the sprint fails, the basilisk simply swims, and it can stay submerged for many minutes, resting on the bottom of a pool until the danger passes.
Status
The common basilisk is Least Concern with a stable population, common along forest waterways and tolerant of disturbed habitat where water and cover remain.
Common Basilisk: common questions
How does the basilisk run on water?
It combines speed, light weight, and a specialised stride. Running upright on its hind legs, it slaps each foot down hard and flat onto the surface, which pushes a column of water downward and briefly creates a pocket of air around the foot. Before that pocket collapses, the lizard whips the foot back up and forward for the next step. Long toes with hinged skin fringes flare out on the downstroke to spread the load over more water. The margin is small, so only young, light basilisks can cross a wide stretch; heavier adults get a few steps and metres before the surface gives way and they carry on swimming.
How far can a basilisk actually run across water?
It depends almost entirely on size. Hatchlings and small juveniles, weighing only a few grams, can scurry across ten to twenty metres of open water and barely get wet. A full-grown adult, an order of magnitude heavier, manages perhaps a metre or two upright before sinking to a swim. The behaviour is an escape tactic rather than normal travel; a basilisk uses it to shoot straight off a bank when a predator appears, buying a head start that a land route would not give, then either reaches the far side or dives.
Is the common basilisk the same as the green basilisk?
They are close relatives in the same genus but different species. The common basilisk, Basiliscus basiliscus, is brown to olive with a pale stripe along the upper lip and body, and lives from Nicaragua south into Colombia. The green basilisk, Basiliscus plumifrons, is bright green with blue and white flecks and a taller double head crest, and is found mainly in Costa Rica, Nicaragua, and Panama on the Caribbean side. Both run on water and share the same streamside lifestyle. Two other basilisk species, the striped and the western, complete the genus.
Do basilisks make good pets?
They are kept in the reptile hobby but they need space and care. A basilisk is nervous and fast, and a frightened one will run headlong into the glass of a small enclosure and injure its snout, so it needs a tall, planted, roomy setup with a large water area for soaking and swimming, high humidity, warmth, and UVB lighting. They are best watched rather than handled. With the right enclosure they can do well and live around eight to ten years, but they are not a casual purchase.