Fiery and fleeting, the shooting star of the vertebrate world has been unveiled. With an out-of-egg lifespan of just four to five months, the chameleon Furcifer labordi leads a briefer life than any other reptile, amphibian, mammal or bird.
After a prolonged incubation, eight to nine months, these bug-eyed chameleons hatch and hit the ground running. They grow up fast and battle their way to a mate before facing an early death. They fight, change colors and perch atop twigs with their prominent horns silhouetted against the spiny thickets of Madagascar’s dry southwestern forests. As the wet season comes to a close in late March, Furcifer labordi slows down. The ephemeral chameleons tumble from trees to their deaths while other nearby chameleon species seek shelter before the harsh dry season begins.
“Pretty amazing,” remarks evolutionary biologist David Wake, “I know of nothing like this.” He’s been studying reptiles and amphibians at the University of California, Berkeley for more than 50 years.
None of the other nearly 30,000 vertebrate species consistently die of natural causes within a year. Yet like cicadas and many other insects that hatch, mate and die within a single season, these chameleons survive for just four or five months, researchers report online June 30 in Proceedings of the NationalAcademy of Sciences. Compared to other vertebrates, the life of F. labordi “is not a little shorter; it’s way shorter,” says Kristopher Karsten of OklahomaStateUniversity in Stillwater, who was lead author on the paper. “They spend 67 percent to 75 percent of their life inside the egg, not outside of it.”
In its “teenage” years, F. labordi adds about 2.6 millimeters to its length each day — a growth rate that collaborator Christopher Raxworthy at the AmericanMuseum of Natural History in New York City calls “off the charts.”
Once F. labordi has matured, life intensifies. Female coloration deepens to signal fertility to suitors. Males puff up in order to appear bigger than they are. And they fight unusually fiercely, Karsten says. Rounds of biting and butting can last for minutes. Aggressive females hiss and battle with undesirable males. Finally, after mating, impregnated females lay their eggs. Then the entire population rapidly grows old and dies.
This chameleon’s romantically tragic life was revealed after Karsten’s team tracked the chameleons in the Ranobe forest in Madagascar, for five seasons between 1995 and 2006 — seeing the same ephemeral life cycle each season.
Still, the researchers wanted to put the short-life hypothesis to the test, Raxworthy says. “Just one observation of one adult in the dry season — once they are supposedly dead — would falsify it.” So the team combed through museum records of all F. labordi ever collected. Sure enough, not a single one had been found alive during the dry season.
Perhaps the long dry season is so tough on this species that it makes more sense for the animal to expend all of its energy during just one season, rather than risk death without mating, Raxworthy says. Maturing so quickly might come with a cost of decreased longevity.
The researchers suggest that other chameleons might have short lives as well and that could account for why chameleons are notoriously hard to keep as pets. But Carlos Haslam at the East Bay Vivarium, a reptile specialty store in Berkeley, Calif., disagrees. He says he’s been rearing long-lived chameleons for more than 15 years. He’s never laid eyes on chameleons from the species F. labordi. “I’m blown away by this,” he says. “It doesn’t make a lick of sense.”
With its all-or-nothing sort of lifestyle, F. labordi might face a particularly high risk of extinction in Madagascar’s diminishing forests, Karsten says. “It’s already a species of concern,” he adds. “We may need to put a little more concern into it.”
