The Chameleon's Secret Weapon

Insects make up most of a chameleon’s diet. But the lizards can also capture prey that’s up to one-third of their body size. The largest chameleons even catch small birds with their tongues. That would be like you lifting a 23 kilogram (50 pound) hamburger with your tongue.

Damman had never before done direct research on animals. Then a biologist came by his lab to ask for his thoughts on a question that had him stumped: How do chameleons’ tongues grasp prey to pull it into their mouths? 

Chameleons don’t wrap their tongues around the food they catch. Some researchers thought the lizards’ tongues used suction. Another theory 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 were able to look at the question with a fresh perspective. “Scientists are often blocked into their small area of research,” says Damman. He immediately thought the mechanism must be some sticky substance on chameleons’ tongues.  

Insects make up most of a chameleon’s diet. But the lizards can also capture larger prey. They nab creatures that are up to one-third of their body size. The largest chameleons even catch small birds with their tongues. That would be like you lifting a 23 kilogram (50 pound) hamburger with your tongue.

Damman had never studied animals directly before. Then a biologist came by his lab. He wanted Damman’s thoughts on a question that had him stumped: How do chameleons’ tongues grasp prey to pull it into their mouths? 

Chameleons don’t wrap their tongues around the food they catch. Some researchers thought the lizards’ tongues used suction. Another idea involved the tongues’ rough surface. Maybe this allowed their tongues to stick to their meals, like Velcro. 

The physicist and the biologist looked at the question together. This helped them to see it from a fresh angle. “Scientists are often blocked into their small area of research,” says Damman. Right away, he thought the answer must be some sticky substance on chameleons’ tongues.  

To test the question, the research 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. 

The chameleon saliva was stickiest when the ball moved quickly. That means when a chameleon’s tongue shoots out at lightning speeds, its force of adhesion—attraction between unlike substances—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 the biology mystery, Damman is ready to explore another one. 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 team needed to test the question. So they placed a small amount of chameleon saliva on a glass plate. They tilted the plate and rolled a small steel ball across it. As the ball moved, they measured how well the saliva slowed it. 

The saliva was stickiest when the ball moved quickly. That revealed what happens when a chameleon’s tongue shoots out at lightning speeds. Its force of adhesion—attraction between unlike substances—increases. When the tongue stops moving, the bond loosens. If it didn’t, the lizards wouldn’t be able to eat their prey without biting their own tongues. 

Damman spent two years tackling the biology mystery. Now he’s ready to explore another one. He’s studying how bees’ tongues capture gooey nectar from flowers. “It’s always interesting to start a new project,” says Damman. “You have to get outside your comfort zone.”