Have you ever been on a dive and suddenly a beautiful sea turtle glides effortlessly over the reef in front of you? You lock eyes, he gives you a cheeky tilt of his shell, showing off his stunning patterns, and with a few flaps of his flippers, he’s outta there. And you’re left thinking… dude, what was going on in his head?
Probably not much ... But there might be a whole lot more happening up there than you realize!
Brainy or Brawny?
Sea turtles have a surprisingly small brain relative to their large body size, and some scientists believe that brain-to-body ratios might correlate with intelligence. So, sea turtles aren't exactly brainiacs. But even though they might not have much going on between the ears, they still manage to do some pretty amazing things that leave scientists scratching their heads. (Hold on, do sea turtles even have ears?!)
Giant Bodies, Tiny Brains: Survival Mode
When sea turtles hatch, their brain-to-body ratio is relatively high because they’re tiny (and sooooo adorable isn't it). This higher ratio may help them handle the mental challenges of their early life. And those early years are incredibly tough! Only around 0.1% of hatchlings make it to adulthood, facing threats like predators, dehydration, and entanglement, to name a few...
As they grow, their bodies get larger, but their brains don’t grow at the same rate. They rely more on their hard shells for protection and less on their brains!
Ears or Not?
Sea turtles do, in fact, have tiny ears, and while they're not visible on the outside of their heads, they help them pick up vibrations in the water. Their ears are covered by a protective layer called the tympanum, and underneath, there’s a layer of fat. Scientists think this fat might help channel low-frequency sounds, similar to how it works in toothed whales. A study found that both hatchling and juvenile loggerhead turtles can hear and respond to low-frequency sounds, suggesting they might be tuned in to these sounds just like some whales. More research is needed to figure out exactly what sea turtles hear!
Pineal Power
Sea turtles rely heavily on instinct for most of their adult lives and use various organs and glands to navigate their world. Just in front of their brain is a pineal gland, which is believed to help some sea turtle species with migration. This gland, located under a thinner area of the skull, can detect light - much like it does in other animals. In mammals, the pineal gland regulates circadian rhythms, but in sea turtles, it may measure environmental light levels and signal when it’s time to head to migration or feeding grounds.
Salty Business
On either side of their brain, sea turtles have two salt glands that are actually much larger than their brains. Sea turtles drink salt water to stay hydrated and eat jellyfish, marine invertebrates, algae, and seagrasses, all of which have the same salt concentration as seawater. However, they need a way to get rid of the excess salt. Since their reptilian kidneys can’t handle large amounts of salt in urine, sea turtles have evolved specialized salt glands (lachrymal glands) near the corners of their eyes. These glands excrete the extra salt, creating a liquid that looks like tears. So, if you’ve ever been lucky enough to observe a sea turtle coming out to nest on a beach and thought it was crying, it’s actually just getting rid of that excess salt!
Solo or Social?
Sea turtles are mostly solo players. They don’t hang out much with each other except during courtship and mating. Olive Ridley turtles are the exception, coming together in huge groups when it’s nesting time. Even when they gather in large numbers for feeding or migration, they don’t do much socializing. Since creating social bonds is often a sign of intelligence, you can draw your own conclusions!
Clever in Their Own Shell-icious Way
For their grand finale, sea turtles flaunt a magnetic sense that still baffles scientists. They can pick up on the Earth’s magnetic field and use it to find their way - how impressive is that? As they mature, female sea turtles refine this sense to detect magnetic landmarks and subtle changes in the field, allowing them to navigate back to their nesting spots year after year, even with shifts in the magnetic field. To find their birth beach, they also use a mix of smells, low-frequency sounds, celestial cues, and other unique features. While we know they’re tuned into these magnetic signals, the exact how-to remains a mystery.
The difficulty in studying sea turtles in the open ocean means there’s still much we don’t know about their behavior. Despite this, decades of research and observations at sea have provided valuable insights into their daily activities, including courtship, mating, and nesting behaviors.
So, are sea turtles smart?
Well, intelligence is a relative term, isn’t it? While they might not be vying for the title of the world’s most intelligent animal, sea turtles are impressive in their own right. They navigate vast oceans, return to their nesting sites with amazing accuracy, and use a variety of senses to survive and thrive. So yes, they’re smart in their own unique way!
Next time you spot a sea turtle, give a nod to their incredible abilities and remember that you’re looking at a creature whose ancestors have been around since the time of the dinosaurs.
Check Out Our Koh Tao Dive Sites Map Here!
Tanote Bay: Dive into stunning coral formations where green turtles are frequently seen gliding gracefully around the reefs.
Liam Thien: This vibrant dive site is bursting with colorful corals and diverse marine life, including green and hawksbill turtles.
Hin Wong Pinnacle: Explore depths and lively marine ecosystems, where you might spot hawksbill and green turtles amidst other sea creatures.
Hin Ngam & Aow Leuk: Discover diverse coral reefs and keep an eye out for juvenile blacktip reef sharks and both green and hawksbill turtles.
Shark Island: With its soft purple corals, this unique site is a regular hangout for both hawksbill and green turtles.
White Rock: A bustling marine hotspot on the west coast, perfect for night dives and spotting turtles.
Twins: Koh Nang Yuan’s popular dive spot, known for its vibrant coral life and frequent sightings of hawksbill and green turtles feeding.
Buddha Point: Famous for its shallow reef and rich coral variety, where hawksbill and green turtles are often spotted.
Shark Bay: Ideal for snorkeling, offering encounters with green and hawksbill turtles, as well as blacktip reef sharks.
