Hunt Like a Chameleon

Buzz! An insect flies through the air, unaware of a chameleon perching motionless nearby. In the blink of an eye, the lizard lashes out its tongue, snags the bug mid-flight, and yanks it into its mouth. We’ve long known about the incredible speed of a chameleon’s tongue. But how it holds on to prey was a mystery—until recently. A team of scientists discovered the chameleon’s secret weapon is super-sticky spit.

A chameleon’s saliva is sticky, like honey. The reptile needs only a thin layer of this substance coating the tip of its tongue to catch its prey, says Pascal Damman, a physicist at the University of Mons in Belgium. He was part of the team that studied the sticky science behind chameleons’ spit. It’s one of the many adaptations that make these animals such great hunters. “They are probably the ultimate predators,” says Damman.

Buzz! An insect flies through the air. It has no idea a chameleon is perched nearby. The chameleon is perfectly still. Then, in the blink of an eye, the lizard lashes out its tongue. It snags the bug and yanks it into its mouth.

Scientists have long known about the incredible speed of a chameleon’s tongue. But they didn’t know exactly how it holds on to prey. A team of scientists recently discovered the chameleon’s secret weapon. It’s super-sticky spit!

A chameleon’s saliva is sticky, like honey. The reptile needs only a thin layer of spit on its tongue to catch prey. It’s one of many adaptations that make chameleons great hunters, says Pascal Damman. He’s a physicist at the University of Mons in Belgium who worked on the discovery. “They are probably the ultimate predators,” he says.

Damman spends most of his time researching physics problems involving how soft, squishy objects like plastic ribbons move. But one day, a biologist came by his lab to ask for his thoughts on how chameleons’ tongues grasp prey to pull it into their mouths.

Scientists already knew that chameleons don’t wrap their tongues around their prey. But there were other theories. Some researchers thought the lizards’ tongues used suction. Another idea was that the chameleons’ tongues had a rough surface that allowed them to make a Velcro-like bond with their meals.

Together, the physicist and the biologist decided to look at the question with a fresh perspective. Damman immediately thought there must be something sticky on chameleons’ tongues to catch its next meal.

Damman doesn’t usually study chameleons. He researches the physics of how soft, squishy objects move. But one day, a biologist came by his lab. The biologist asked Damman how he thought chameleon tongues grasp prey.

Scientists knew that chameleons don’t wrap their tongues around their victims. But there were other theories. Some people thought the lizards’ tongues used suction. Others thought they had a rough surface that helped them stick like Velcro.

Damman and the biologist decided to work together. They wanted to look at the question in a new way. Damman immediately had his own theory. There must be something sticky on chameleons’ tongues, he thought. 

The team collected a small amount of chameleon saliva on a glass plate. They tilted the plate and rolled a small steel ball across it to measure how well the saliva slowed the ball. They then used that information to create mathematical models of the sticky force. “Without math, you can’t solve anything,” says Damman.

The team found that the chameleon saliva was stickiest when the ball moved quickly. That means when a chameleon’s tongue shoots out at lightning speeds, the spit’s force of attraction increases. When the tongue stops moving, the bond with its prey loosens. Otherwise, chameleons wouldn’t be able to eat their prey without biting their own tongues.

After spending two years tackling this mystery, Damman decided he wasn’t done with biology. He’s now investigating how bees’ tongues capture viscous nectar from flowers. “It’s always interesting to start a new project,” says Damman. “You have to get outside your comfort zone.”

The scientists collected a small amount of chameleon saliva on a glass plate. Then they tilted the plate and rolled a small steel ball across it. They measured how much the saliva slowed down the ball. That helped them calculate how the spit would affect other things.

The saliva was stickiest when the ball moved quickly. When the ball rolled slowly, there was less sticky force. That means a chameleon’s tongue is stickiest when it hits its prey at lightning speed. When the tongue pulls back and stops moving, its grip loosens. That allows the chameleons to swallow the prey in their mouths.

Damman spent two years investigating this mystery. But he decided he isn’t done with biology yet. He’s now investigating how bees’ tongues capture sticky nectar from flowers. “It’s always interesting to start a new project,” he says. “You have to get outside your comfort zone.”