Science News

Loud Lizards

Lizards have evolved to play it cool, blending into background foliage to remain hidden from predators. But what do they do when they actually need to get noticed - for example, to attract a mate? New research into lizards has found that the animals "shout" to get noticed against busy leafy backgrounds - but rather than shouting audibly, they use visual tricks. Anole lizards usually signal that a territory is theirs by bobbing their heads up and down. And sometimes,they also inflate their throats to display a large, pink pouch. But these demonstrations can be hard to notice against a distracting background of moving foliage. Researchers from the University of California filmed two species of Anole lizards in Puerto Rico, and found that the greater the visual disturbance in their background (such as moving leaves), the more the lizards bobbed their heads, displayed their pouches and lashed their tails. It's a bit like dancing more and more crazily in a dark nightclub to make an impression on the ladies. The researchers say the lizards need to strike a balance between being showy enough for rivals and mates to pick them out, but subtle enough not to be seen by predators. Similar adaptations have been seen in birds, who literally shout louder to be heard over traffic in busy cities compared to their rural counterparts.

25th Feb 2007