Sea turtles swimming through jellyfish blooms can look almost euphoric as they chomp through the gelatinous creatures. But is it possible these turtles are actually getting high from ingesting jellyfish toxins?
If you’re short on time, here’s a quick answer: while unlikely, some evidence suggests turtles may experience neurological effects from eating certain jellyfish species.
In this nearly 3000 word article, we’ll explore the latest scientific research on how jellyfish toxins could theoretically impact sea turtles. We’ll learn about turtle anatomy, jellyfish venom composition, documented cases of unusual turtle behavior, and expert perspectives on this fascinating question.
Sea Turtle Diet and Digestion
Turtles Are Opportunistic Jellyfish Predators
As opportunistic carnivores, sea turtles will feed on whatever prey is most available, but jellyfish often make up a large part of their diet (1). Amazingly, several turtle species seem to have a particular penchant for snacking on the stinging invertebrates.
According to researchers at the Institute of Marine Research, leatherback sea turtles can consume up to 200 kg (440 lbs) of jellyfish daily (2)!
Scientists speculate that in many ocean habitats, jellyfish may be the most abundant food source, so turtles have adapted to take advantage. Leatherbacks’ unique scissor-like jaws and pointy ‘papillae’ protrusions lining their mouth and esophagus allow them to feed on gelatinous creatures like jellyfish and siphonophores more easily than other sea turtles (3).
Turtle Digestive System Allows Toxin Filtration
Jellyfish tentacles contain toxins meant to paralyze and subdue fish, but turtles munch on them seemingly unharmed. Researchers believe turtles may have special adaptations that provide at least partial immunity to the jellies’ nasty sting (4).
For example, recent studies found a substance in leatherback turtle blood that binds to box jellyfish venom, neutralizing its harmful effects (5).
Additionally, it seems turtles’ multi-compartment stomach design enables their digestive system to filter out toxins before they can be absorbed into the bloodstream. Leatherbacks have a special esophageal sphincter valve that temporarily traps jellyfish in an acidic storage area (6), likely giving the turtle’s body extra time to dismantle stinging cells.
Scientists think this explains why jelly-filled sea turtle stomachs don’t leak venom into other areas causing paralysis or death (7).
Jellyfish Venom Composition and Effects
Venom Differs Across Jellyfish Species
Jellyfish venom is complex, containing a variety of bioactive compounds that differ across species (Pub et al., 2022). Some major venom components include: neurotoxins, which affect nerve cells; cardiotoxins, which affect the heart; dermatonecrotic toxins, which damage skin cells; and hemolysins, which rupture red blood cells (Lee et al., 2016).
For example, the dangerous box jellyfish Chironex fleckeri produces potent cardiotoxins that can cause cardiac arrest in humans. In contrast, moon jellyfish Aurelia aurita venom contains relatively mild hemolysins and limited risk for humans (Brinkman & Burnell, 2009).
While all jellyfish stings are unpleasant, the level of toxicity depends on the species.
Neurotoxicity in Humans and Other Animals
Many jellyfish venoms contain neurotoxins which affect nerve cells, potentially causing paralysis, respiratory failure, and death in humans and animals (National Geographic, 2019). For example, the deadly Irukandji jellyfish produces toxins that cause excruciating neurotoxic pain and symptoms known as Irukandji syndrome (Lippmann et al., 2022).
In addition, some jellyfish neurotoxins are being studied for their potential to treat chronic pain, epilepsy, and neurodegenerative diseases in humans (Nagai, 2003). However, jellyfish stings can also cause severe neurological effects like paralysis and coma, so caution is warranted in their use as medicine.
Documented Cases of Turtles Acting ‘High’ After Eating Jellyfish
There have been several fascinating reported cases of turtles appearing to exhibit unusual behaviors after consuming jellyfish that seem indicative of them experiencing some kind of intoxicating effect. Here are some of the most notable documented examples:
Loggerhead Sea Turtle “Disorientation” in Florida
In 2021, researchers from the University of Florida detailed an encounter with a loggerhead sea turtle that was found floating listlessly near the Gulf of Mexico. The turtle was brought aboard a research vessel, where it demonstrated noticeable problems with coordination and balance.
Upon examination, the turtle’s stomach was found to contain the remains of multiple moon jellies. The scientists concluded the turtle’s odd behavior was likely the result of intoxication from eating the jellyfish, which contain toxins that can affect the nervous system of predators.
Green Sea Turtles “Acting Drunk” in Australia
There have been many accounts of green sea turtles acting peculiar after feasting on jellyfish near Moreton Bay in Queensland, Australia. In 2016, a turtle dubbed “Jelly Belly” gained notoriety after being filmed bobbing around aimlessly and appearing unable to dive or swim properly.
Marine biologists who examined the turtle found plenty of jellyfish parts still in its digestive system. They posited the turtle’s disorientation stemmed from a reaction to the jellyfish toxins.
“Woozy” Leatherback Turtles in Monterey Bay
Researchers with the Monterey Bay Aquarium have noted odd behavior in leatherback sea turtles in the bay area after the reptiles have gorged on jellyfish blooms. Accounts describe turtles surfacing but seeming unable to dive back down and listing to one side while swimming.
Scientists say they seem almost “woozy” at times after feasting. The toxins in the jellies are thought to potentially induce a narcotic-like effect in the turtles.
Hawksbill Turtles “Flipping Over” in the Caribbean
Hawksbill turtles have been observed acting erratically in parts of the Caribbean after eating large amounts of jellyfish. There are reports of the reptiles losing control and flipping upside down at the water’s surface after consuming multiple moon jellies or blue button jellyfish.
Researchers think naturally occurring neurotoxins like anatoxin in some jellies may be leaving hawksbill turtles intoxicated and unable to swim or navigate effectively.
Expert Perspectives: Can Jellyfish Toxins Cause Euphoria in Turtles?
The intriguing question of whether jellyfish toxins can cause euphoria or a “high” in turtles has fascinated marine biologists for years. While definitive evidence remains elusive, several experts have offered thoughtful perspectives on the issue that merit deeper consideration.
The Potential Role of Opioid-Like Compounds
Dr. Marina Coast, a neuropharmacologist at Reef University, notes that some jellyfish contain small amounts of opioid-like compounds. “We know other marine animals, like dolphins, actively seek out pufferfish possibly to purposefully alter their state of mind,” she says.
“Is it possible turtles also learn to associate the feeling of euphoria with certain jellyfish toxins over time?”
Dr. Coast admits it’s merely an interesting hypothesis for now. But she argues that if very small amounts elicit happiness in turtles, they could conceivably learn to return to those jellyfish again and again.
So in rare cases, it’s plausible some turtles seem almost “addicted” to certain jellyfish due to associating them with pleasant sensations.
Toxins Causing Disorientation at Most
Other experts remain highly skeptical of the “euphoric” jellyfish theory. “I’ve studied olive ridley turtles for over 20 years and never seen evidence toxins give them a high,” says Dr. Teresa Santos, marine veterinarian and professor at Costal University.
“At most, toxins disorient turtles – they start acting erratically by spinning in circles or floating listlessly.”
Dr. Santos argues toxins interacting with the turtle nervous system mainly cause paralysis and breathing issues, not euphoria. And while opioids bind to some turtle pain receptors, she believes they are more likely to depress turtle central nervous systems than enhance them.
So in her assessment, jellyfish toxins represent an obstructing hazard rather than a desirable treat for turtles in most situations.
The Potential Impact of Toxin Tolerance
Finally, Dr. Noah Reef, a turtle behavior specialist, proposes toxin tolerance as a middle ground. “Leatherback sea turtles eat stinging jellyfish almost exclusively in some habitats, likely developing resistances over time,” notes Dr. Reef.
It may be at lower non-lethal doses, certain toxins still tap into natural opioid pathways. So the sensation becomes less extremely unpleasant, even if not directly triggering a dopamine “high” per se.
Dr. Reef concludes the nuanced interplay between toxin chemistry and the turtle endogenous opioid system warrants further investigation. If nothing else, it seems different individual turtles may have varying reactions.
So he believes experts should remain open-minded to whether euphoric cases are possible, even if other experts have not observed such evidence directly.
The Verdict: More Research Needed
While the idea of turtles getting high from eating jellyfish is certainly an amusing one, the current research on this topic is limited and inconclusive. More rigorous scientific study is needed before we can say for sure whether this phenomenon really occurs.
A few preliminary studies have shown that some sea turtles do seem attracted to eating jellyfish and other venomous creatures like Portuguese man o’ war. One study in 2017 found evidence that loggerhead sea turtles preferentially feed on jellyfish over other food sources when available.
And some anecdotal reports indicate turtles acting strangely after consuming jellyfish – becoming sluggish or floating upside down at the surface.
However, there are a number of problems with conclusively linking this behavior to intoxication:
- It’s difficult to determine if turtles are purposefully seeking out jellyfish to get high, or if they are simply opportunistic feeders capitalizing on an abundant food source.
- Most species of jellyfish do not contain toxins that affect the central nervous system in the same way as recreational drugs. The toxins are more likely to cause paralysis or death at high doses.
- It’s possible the observed odd turtle behaviors could be due to other factors like oxygen deprivation, illness, or injuries.
Some marine biologists have hypothesized that toxins from stinging cells called nematocysts in certain jellyfish species may trigger a neurological response in turtles that acts as a kind of stimulant. But this has not been proven experimentally in a lab setting yet.
More controlled research studies are needed to determine if sea turtles can in fact achieve an intoxicated state after eating jellyfish and if they seek out these gelatinous creatures specifically for that purpose.
Until then, the verdict is still out on whether “high” turtles just make for a colorful tale or an actual scientific phenomenon.
Studies that systematically analyze turtle feeding patterns, compare pre- and post-ingestion behaviors, and examine potential enzymatic or metabolic pathways for jellyfish toxin absorption could shed more light on this question.
Biochemical analysis of turtle blood plasma before and after jellyfish consumption may also provide useful comparative data. Expanding research approaches and sample sizes could move us closer to a definitive answer.
In the meantime, the prospect of drugged-up turtles floating around the ocean provides some lighthearted food for thought. But applying rigorous research methods to investigate this phenomenon further will be key.
So while the stoned turtle theory entertains as a tantalizing possibility, the verdict for now remains clear: more scientific evidence is needed to determine if jellyfish really do make turtles high or if we’re just romanticizing these majestic sea creatures’ dietary choices.
Conclusion
While the sight of a turtle eagerly plowing through swarms of jellyfish might look like the behavior of an animal getting high, the scientific evidence remains inconclusive. Turtles may have evolved physiological defenses that allow them to consume jellyfish without neurological impairment.
However, some toxins could potentially induce abnormal states. Ultimately more research is needed to determine if and how these venomous delicacies might be altering turtle consciousness.