SLEEPING SHARK CAVE
Sleeping Shark Cave, about a 30-minute boat ride from Isla Mujeres, is a fascinating site where sharks appear to sleep in caves, first discovered by local fisherman "La Valvula." This unique dive location has drawn visitors for decades and was documented by Jacques Cousteau and Ramon Bravo in 1970.
Depth
18 meters / 60 feet
Boat Ride
30 minutes
Dive Type
Reef, Drift, Tunnels, Swim Throughs
Experience Level
Open Water Diver, Recent Dive Experience
Average Visibility Underwater
20 mt / 65 feet
Average Water Temperature
26 C°/ 79F°
Dive Time
40 - 45 minutes, Safety Stop Required
National Park
No
In 1969, fisherman Carlos Garcia Castilla, known as "Válvula," discovered the cave Los Cuevones while lobster hunting in Isla Mujeres. Initially frightened by resting sharks inside, he challenged the belief that sharks do not sleep. Diver Ramon Bravo, initially skeptical, later confirmed this, attracting the attention of scientists Dr. Shelton Applegate and Dr. Eugenie Clark.
In 1970, Jacques Cousteau's team filmed a documentary about the cave, with Ramon as a guide. While Cousteau sought personal recognition, Ramon had already credited Válvula in his published images.
The cave's unique water conditions—higher oxygen and carbon dioxide levels and lower salt concentrations—cause sharks to relax, with theories suggesting this aids in parasite removal by remora fish or mimics Nitrogen Narcosis.Â
After Ramon Bravo’s passing in 1998, his ashes were scattered at the cave's entrance, a testament to his contributions to marine conservation. The site, located 30 minutes from the island at a depth of 20 meters, remains a popular but unpredictable diving destination.