Costa Rica’s rainforests are home to incredible creatures, but few are as mesmerizing as the basilisk lizards, famous for their ability to run on water. At Arenal Enjoy, you might spot two spectacular species: the Green Basilisk (Basiliscus plumifrons) and the Brown Basilisk (Basiliscus vittatus).
These “Jesus Christ lizards” don’t just walk on water – they can sprint across it to escape predators! This amazing ability has amazed both scientists and travelers alike. But there’s much more to these reptiles than their miraculous aquatic dash. Let’s get to know them better!
The Basilisks of Arenal
1. Green Basilisk (Basiliscus plumifrons)
Nickname: “The plumed basilisk” (for its dramatic crests)
Appearance:
- Bright emerald green body
- Males have three distinctive crests (head, back and tail)
- Females are smaller with just one head crest
Behavior and superpower:
- Water-running speed: Up to 1.5 meters per second!
- When threatened, they drop from trees into water and run on their hind legs
- Excellent climbers and swimmers
Reproduction:
- Females lay 5-15 eggs in soft soil or leaf litter
- Eggs hatch in 8-10 weeks; babies can run on water immediately!
Fun fact: Their crests are used to attract mates and intimidate rivals – the bigger, the better!
2. Brown Basilisk (Basiliscus vittatus)
Nickname: “The striped basilisk”
Appearance:
- Brown or olive color with dark stripes along the body
- Males have a small head crest; females lack one
Behavior and superpower:
- More terrestrial than green basilisks but equally skilled at water-running
- Often seen sunbathing on rocks or logs near streams
Reproduction:
- Lay 4-12 eggs per clutch
- Hatchlings are independent at birth and instinctively flee predators by running on water
Did you know? This species is more adaptable and often seen near human settlements
How Do Basilisks Run on Water?
Their secret lies in:
✅ Lightweight bodies + long toes with fringed scales that trap air bubbles
✅ Rapid leg movement (up to 20 steps per second) to stay on the surface
This ability isn’t just for show – it’s a key survival tactic against predators like birds, snakes and mammals!
From Basilisks to Dinosaurs: The Evolution of Bipedal Running
Scientists believe the basilisk’s two-legged running mimics how some ancient reptiles moved, eventually leading to the evolution of bipedal dinosaurs like Tyrannosaurus rex!
- Basilisks switch from four legs to two when reaching top speed, just like some early dinosaurs
- This adaptation likely helped prehistoric reptiles escape predators and hunt more efficiently
Where to Spot Basilisks
🔹 Near streams, ponds or riverbanks (their favorite escape routes)
🔹 Sunbathing on rocks or low branches in the morning
🔹 Brown basilisks are often spotted near stacked wood and open areas away from water sources
Pro tip: Move slowly and avoid sudden movements for your best chance to observe them
Want to learn more about Arenal’s wildlife? Check out our other blog posts or join one of our guided nature tours! 🦎💦
