Dewlaps and Displays
A Close-up of Anolis gundlachi
A spotlight shines on a lone A. gundlachi in the middle of the stage. The lizard is standing at attention. To the right of the stage, in shadow, is a human narrator dressed in brightly colored scarves.
Narrator: A. gundlachi is a mid-sized anole lizard common to the mountains of El Yunque. As you can see, it has a pointed snout, a thin tail, and four legs, each ending in five long, clawed toes. It is a cute creature, don’t you think? Males are always larger than females. They can reach up to 75 mm from their snout to their vent. The vent is where they—ahem—poop. Their tail is not included in the measurement. In color, A. gundlachi is brown or olive brown. Notice the number of dark markings on the sides. The lizard can also have a series of dots and lines of yellow or green-yellow color.
The spotlight zeroes in on the face of the lizard.
Narrator: A. gundlachi has a yellow chin. That is why its nickname is the yellow-chinned anole. It also has blue eyes and a large brown or yellow-brown dewlap.
The spotlight zeroes in on the dewlap.
Narrator: A dewlap is a fanlike extension, like a huge Adam’s apple, below the neck. It is usually more colorful in the male than the female.
Several anoles of various colors parade across the stage. The colors range from bright green to somber brown. When they reach the end of the stage, they turn and walk back. Occasionally, they stop and turn their bodies in a complete circle.
Narrator: Most anoles are able to change colors. They assume different tones of brown. If they are green, they change to brown or almost black. Although many people think otherwise, color changes do not seem to be a response to background colors in the forest. Rather, they seem to result from a reaction to excitement or temperature change.
The audience claps enthusiastically for the bright green anole.
Several anoles stand on the stage. At a command from the anole in the center, each lizard performs a specific movement. One expands and contracts the dewlap below its neck. Another performs a series of push-ups. A third bobs its head. A fourth sticks out its tongue. A fifth wags its tail. The anole in center turns to the right, then to the left. A ridge on its back stiffens and relaxes.
Narrator: When they want to show they are in control—in today’s language, “act macho” —anoles expand their dewlap. This happens during courtship, when they are afraid, or when they defend their territory. The dewlap swells into a balloonlike sac below the neck. This is called a fan display because the dewlap looks like an open fan. A variety of other gestures often follow the fan display. Our performers are showing you some of them. Sometimes these displays help anoles recognize others of the same species. For example, all A. gundlachi anoles perform the same gestures. When several different anole species live in the same area, the displays become more complex and the dewlaps become more colorful.
The audience’s obvious favorite is the anole doing push-ups.
Two anoles enter the stage from opposite sides. They walk toward each other. When they are several feet apart, they “face off.” The lizard with green-yellow lines challenges the other by performing displays. Its dewlap swells, and it does push-ups, head bobs, and so on. The motions have the grace of a Japanese kabuki dancer and the speed of a karate warrior. The other lizard rises to the challenge and performs its own series of displays. After several minutes, the anole with green-yellow lines nips the other. The other falls, then gets up. Both anoles move to opposite sides of the stage. The nipped anole exits. A third anole flits into the spotlight. The victor approaches the third and begins to perform a combination of displays again. The third anole runs away. The victor follows. For several minutes the anoles run and follow, run and follow. Then the third anole stops and lets the victor catch up. They walk off the stage together.
Narrator: When one anole enters the territory of another, a showdown takes place. This is a dramatic display of ritual behavior. The resident anole performs a fan display as a challenge to the newcomer. The reaction to this display determines whether the newcomer is male or female. Males rise to the challenge with similar displays. Females do not react, or they flee. Contests between males may be settled merely by these displays. Sometimes the two lizards bite each other, but they do not cause much damage. If a male falls to the ground, the victor often forgets about him. Females usually run coyly from males who are in the mood for reproduction. If the male perseveres and all goes well, the female finally allows the male to overtake her. Reproduction occurs.
The audience claps wildly, stands, and shouts "Bravo!"
The dance is a success.