How Do Alligator Snapping Turtles Lure Fish? The Tongue Trick

The worm on the tongue

The lure is a small, fleshy appendage, described by scientists as vermiform, which simply means worm-shaped. It sits on the tip of the tongue of the alligator snapping turtle and is pinkish, standing out sharply against the gray inside of the mouth.

The turtle can move the appendage with muscles in the tongue, making it twitch and curl like a live worm. This kind of trick, where a predator imitates something harmless or tasty to draw prey close, is called aggressive mimicry. Alligator snapping turtles (genus Macrochelys) are the only turtles known to have such a lure.

How the ambush works step by step

1. Settle in. The turtle picks a spot on the bottom of murky water, often near sunken logs or roots, and stays completely still. Algae growing on its rough shell help it blend in with the mud and debris.
2. Open wide. It opens its jaws and holds them open. The gray, camouflaged mouth lining makes the open mouth look like a dark hollow, with only the pink lure catching the eye.
3. Wiggle the lure. The turtle moves the appendage so it looks like a worm struggling in the current.
4. Snap. When a fish comes close enough to investigate, the jaws close with great speed and force. The prey is swallowed whole, cut in two by the sharp edges of the beak or pinned on its hooked tips.

Because the turtle hardly moves, it uses very little energy while waiting. That fits its slow, low-energy lifestyle: alligator snappers can stay underwater for around 40 to 50 minutes between breaths.

Who uses the lure most?

The lure works best for catching small fish such as minnows, and it is used mainly by younger turtles, often during the day. A small turtle can get much of its food this way.

Large adults are a different matter. A turtle weighing 30 kg (66 lb) or more needs far more food than an occasional minnow, so big adults rely mostly on active foraging, especially at night. They move slowly along the bottom and use their sense of smell, pumping water in and out of the throat to sample chemical traces of prey. In this way they can find mud and musk turtles buried in the riverbed, dead fish and other food the lure would never attract.

So the famous tongue trick is real, but it is only one part of how these turtles feed. For the size differences between young and old turtles, see how big do alligator snapping turtles get?.

What else do alligator snapping turtles eat?

Alligator snappers are opportunistic: they eat almost anything they can catch or find. Recorded foods include:

• Fish and fish carcasses, the most frequently found prey in many studies
• Other turtles, especially mud and musk turtles; in one Louisiana study turtle remains dominated the stomach samples, although hard shell fragments may linger in the gut longer than soft food
• Mollusks such as mussels and snails, plus crayfish, worms and insects
• Amphibians and reptiles, including frogs and snakes, and very rarely small alligators
• Birds and mammals that swim or come to the water’s edge, such as ducks, muskrats, nutria, squirrels and opossums
• Carrion, making them important scavengers that help clean rivers

Plant food is a surprise to many people. In one study of turtles sampled between spring and fall, acorns from riverside oaks made up more than half of the stomach contents by volume, while fish were eaten most often but made up a small share of the volume. Acorns that pass through the turtle can still sprout, so the turtles may help spread oak trees along rivers.

How is this different from the common snapping turtle?

The common snapping turtle has no tongue lure. It hunts by lying buried in mud with only its eyes and nostrils showing, striking at prey that passes, and by actively searching ponds and streams for food. It also eats a large amount of water plants. The two species are compared in detail in alligator snapping turtle vs common snapping turtle.

Other animals that use lures

Luring prey is rare, but the alligator snapper is not alone. Deep-sea anglerfish dangle a glowing “fishing rod” in front of their mouths, and some snakes, such as young copperheads and death adders, wiggle a brightly colored tail tip to attract frogs and lizards, a behavior called caudal luring. The alligator snapping turtle’s version is unusual because the lure sits inside the mouth itself, so the prey swims straight into the trap.

Myths about the tongue lure

A common belief is that the turtle catches all its food with the lure while sitting still. In reality, large adults find most of their food by active foraging. Another myth is that the lure is a separate organ or a parasite. It is a normal part of the tongue, present in every alligator snapping turtle.