Hawaiian green sea turtles, or honu, hold a special place in Hawaii’s culture and marine ecosystems. Beloved for their gentle nature and graceful presence, these turtles are often spotted by travelers and snorkelers exploring Hawaii’s pristine waters. Beyond their photogenic charm, honu symbolize longevity, good luck, and a deep connection to the islands’ rich heritage. Read on to discover why these ancient mariners captivate locals and visitors alike, and what you need to know to enjoy them responsibly.
1. They can hold their breath for hours
Sea turtles have an impressive lung capacity – while resting, they can slow their heart rate and remain underwater for up to five hours! That said, when swimming and feeding, they typically come up for air every 15–30 minutes. If you’re snorkeling and notice a turtle surfacing, it’s likely just taking a quick breath before diving gracefully back down.
2. Their shells are part of their skeleton
Unlike other marine creatures with external “armor,” a sea turtle’s shell is actually part of its skeletal system. Made of bone and covered in keratin (the same substance found in human fingernails), it grows with the turtle throughout its life. Pay close attention while snorkeling—you might recognize individual turtles by their unique shell patterns.
3. They have built-in GPS
Ever wonder how sea turtles can navigate vast ocean distances to find the same nesting beach where they were born? Research suggests they utilize Earth’s magnetic fields, thanks to special receptors in their brains. These built-in “GPS” signals guide them across thousands of miles of open ocean—a truly remarkable feat of nature.
4. Some turtles can grow to over 700 pounds (320 kg)
While Hawaiian green sea turtles typically max out around 500 pounds, the massive leatherback sea turtle can weigh over 700 pounds and measure up to seven feet in length. Though leatherbacks are less common to see while snorkeling in Hawaii, their jellyfish-based diet and large, leathery shells set them apart from other sea turtles.
5. They help keep coral reefs healthy
Turtles play an essential role in maintaining marine ecosystems. By feeding on seagrass and algae, they prevent overgrowth that could suffocate coral reefs. Their presence helps balance the ocean’s delicate food chain, making them a crucial part of the underwater world you explore while snorkeling.
6. They can live for over 100 years
Much like their land-dwelling tortoise cousins, many sea turtles boast incredibly long lifespans. Scientists estimate that some species can live beyond a century, adding to their mystical, ancient aura beneath the waves.
7. They can sleep underwater
Sea turtles often rest in underwater caves, coral reefs, or rocky crevices. By slowing their metabolism, they can remain submerged for several hours while sleeping. Keep your eyes peeled for a resting honu—sometimes, you might spot a turtle snoozing peacefully under a ledge.
8. Hatchlings face an incredible journey
While you might not spot hatchlings while snorkeling, every sea turtle begins life in a dramatic dash for survival. Upon hatching, baby turtles must scramble from their nest to the sea, dodging predators like birds and crabs. Only a small percentage make it to adulthood—so each adult honu you see is a testament to nature’s resilience.
9. They are protected by law
Because of their endangered status, many sea turtle species, including the Hawaiian green sea turtle, are protected under national and international laws. It is illegal to touch, chase, or harass sea turtles while snorkeling. Observing them from a respectful distance ensures their safety and preserves their natural behaviors.