The lizard that runs across the surface of water
This lizard can literally run across the surface of water without sinking.
Which one is REALLY true about the Basilisk Lizard?
The short version
The basilisk ('Jesus Christ lizard') sprints upright across water on its back legs, slapping the surface up to 20 times a second so each step traps an air pocket before water rushes in. A young one can cross 15+ feet of water, and it's also a strong underwater swimmer.
Why it's so weird
- ✓The Basilisk Lizard can sprint straight across the top of the water without sinking.
- ✓The Basilisk Lizard runs upright on its two back legs, slapping the surface as it goes.
- ✓The Basilisk Lizard traps a tiny pocket of air with each footstep before water rushes in.
- ✓The Basilisk Lizard can cross more than fifteen feet of open water when it is young.
- ✓The Basilisk Lizard hits the surface up to twenty times every second, and is also a great swimmer.
You could line up about 2 of them along a 7-year-old!
The full story
This lizard can sprint straight across the top of a pond without ever sinking. Meet the basilisk, nicknamed the Jesus Christ lizard for its miracle move. When a predator strikes, it drops onto the water and runs upright on its two back legs, slapping the surface so fast that it never breaks through. Each footstep creates a tiny pocket of air, and the lizard pulls its foot out before the water can rush in and swallow it. A young basilisk can scramble across more than fifteen feet of open water this way, hitting the surface up to twenty times every second. If it finally does slow down and sink, no problem, it is also an excellent swimmer and can hold its breath underwater for many minutes. Pure panic, turned into a superpower. Follow for more weird animal facts.
A basilisk is far too heavy for the water's thin 'skin' (surface tension) to hold up, so instead it wins a race against sinking. Every time a back foot smacks down hard and fast, it pushes water away, and that water pushes the lizard back up. The fast-moving foot also leaves a little pocket of air behind it, and the lizard yanks its foot out before the water rushes in and grabs it. This only works because it is quick and light — its feet hit the surface up to 20 times a second, and small young ones are the easiest to keep on top.
📚 Source: Physics World — Could athletes mimic basilisk lizards and turn water-running into an Olympic sport? ↗Scientists filmed live basilisks running across water with high-speed cameras and measured the swirls their feet stirred up, proving the upward push comes from slapping and stroking the water — not from surface tension.
📚 Source: Hsieh & Lauder, 'Running on water: Three-dimensional force generation by basilisk lizards,' PNAS (2004) ↗Watch the 45-second version
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Basilisk Lizard gallery
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“The Basilisk Lizard can sprint straight across the top of the water without sinking.”
“The Basilisk Lizard is the only mammal on Earth that can truly fly.”
“The Basilisk Lizard runs upright on its two back legs, slapping the surface as it goes.”