Although jellyfish provide no proteins, fats, or carbohydrates, many animals eat jellyfish. In some cultures, consuming jellyfish is part of celebrating special festivals or holidays. Scientists think animals that eat jellyfish are benefiting from fatty acids in jellyfish tissues that are vital to supporting growth and reproduction processes.
Jellyfish are invertebrate salt-and freshwater-dwelling cnidarians that are anatomically related to sea anemones, hydrozoans, and corals. “Jellies” are not fish because they do not have backbones nor do they breathe using gills.
Instead, jellyfish absorb oxygen through their thin skin. This oxygen is then transported throughout their bodies via vein-like cavities extending from their intestinal system.
10 Animals that Eat Jellyfish
Another reason why animals eat jellyfish is because there are so many of them floating around in the seas and oceans. In other words, the high quantity and sluggish movement of jellyfish make up for its mostly innutritious food quality.
Below is a list of the top 10 jellyfish-eating animals, along with some interesting facts about them.
The largest whales can take in between 5000 and 10,000 gallons of water in one gulp when feeding. Also called “filter feeders”, whales filter out edible creatures like crustaceans, plankton, fish, and jellyfish before swallowing some of the water and spitting out the rest.
Hermit and arrow crabs are known for their insatiable appetite for jellyfish. They spend most of their underwater life scavenging the seafloor for anything that drifts by, especially jellyfish and fish. Most crabs blend well into the seafloor’s multicolored landscape, which makes it easier for them to suddenly reach out and grab an unsuspecting jellyfish with a nimble claw.
3. Gray Triggerfish
Living in reefs, lagoons, and shallow water areas in the western Atlantic Ocean, the gray triggerfish uses its sharp teeth and strong mandibles to deliver fatal bites to jellyfish. In fact, their sharp teeth can easily pierce the hard shells of lobsters, sand dollars, and crabs. Add their ability to dart quickly through the water and a slow-moving jellyfish doesn’t have much of a chance of escaping a hungry gray triggerfish.
4. Ocean Sunfish
Living in tropical and temperate oceans, ocean sunfish are the heaviest bony fish known, reaching over 10 feet in length and weighing as much as 5000 pounds. Although sharks like the great white are known to weigh over 5000 pounds, sharks are cartilaginous fish, not bony fish.
Guess what an ocean sunfish’s favorite food is? You guessed right–jellies! One reason why ocean sunfish get excited when they see a school of jellyfish is that there are always enough jellyfish to eat to quickly get rid of hunger pangs while supporting their huge size.
Seabirds like albatrosses, fulmars, and diving petrels have excellent eyesight that allows them to detect prey moving on or just below the surface of the water. The seabird’s flawless diving and snatching technique make it effortless for them to capture jellyfish. Seabirds eat jellyfish by swooping and pecking them until there is nothing left of the jellyfish but its tentacles.
A member of the sea slug family, the bottom-dwelling nudibranch is famous for having colorfully patterned bodies that can take a variety of weird shapes. A type of nudibranch called aeolid is capable of eating a whole jellyfish, including the stinging tentacles which other animals deliberately avoid.
Aeolids not only prey on jellyfish but they steal from them, too. What’s fascinating about this theft is what aeolids steal–tiny pieces of tissue containing stinging chemicals. They then store these pain-causing cells in their horns (cerata) extending outward from their bodies. When a predator approaches too closely to an aeolid equipped with jellyfish stings, that predator will get stung!
A recent study investigating the diet of penguins discovered, much to the surprise of marine zoologists, that penguins are regular consumers of jellyfish. In fact, penguins deliberately look for jellyfish when other food sources are scarce, they want to stave off hunger pangs.
This is another instance when jellyfish seem to be their own worst enemy simply because there are so many of them and they tend to travel in groups called “swarms”. Only larger, stronger jellyfish like the Box jellyfish may be seen swimming alone in the water.
8. Leatherback Sea Turtle
If you asked a leatherback sea turtle what he or she wanted for breakfast, lunch, and dinner, it will inevitably reply: “Jellyfish”! The biggest turtle in the world (up to six feet long and weighing over 1000 pounds), leatherback turtles do not have hard shells or scales.
They protect their inner body with a thick layer of tough, rubbery skin that effectively protects them as adults. Primary predators of leatherback sea turtles take advantage of their defenseless eggs and newly hatched turtles.
If a jellyfish thinks it can evade a hungry leatherback turtle by going deeper under the surface, that jelly had better think again. Leatherbacks can dive deeper than most other sea creature divers–over 3500 feet deep!.
There are three reasons why sharks eat jellyfish:
- Jellyfish are incredibly slow-moving creatures. Sharks are incredibly fast-moving creatures.
- Jellyfish are literally everywhere. You can find jellyfish floating around in the most desolate areas of seas and oceans.
- Sharks will eat anything.
About a dozen species of jellyfish are safe for human consumption. Jellyfish is considered a delicacy in many southeast and east Asian countries, including China, Japan, Taiwan, Vietnam, and the Philippines.
Jellyfish will spoil rapidly at temperatures between 50 and 70 degrees Fahrenheit. Unless you plan to eat a jellyfish immediately after catching it, you had better take the time to preserve the jelly with an alum-salt mixture that dehydrates jellyfish meat. Possible consequences of eating spoiled jellyfish include Salmonella or listeria infections.