Charles Darwin hated the peacock — hated it — at one point writing that he was simply sickened by its ostentatious feathers. He couldn’t for the life of him figure out why a creature would essentially beg to be hunted, seemingly in wanton disregard of his new theory of evolution, which is about the survival (not the evisceration) of the fittest.
The answer, Darwin eventually realized, is the principle of sexual selection. With its glorious plumage, the peacock is essentially saying to the peahen, “I’m healthy, and also I might have a bit of an ego problem.” It’s a drive so strong that it outweighs the risk of predation and justifies the tremendous energy the peacock puts into growing the feathers, not to mention lugging them around.
But sexual selection is far from a solely visual process. Behold the superb lyrebird, whose calls are surely the most impressive in the animal kingdom. It has the uncanny ability to perfectly mimic the sounds of the Australian forests it calls home, from camera shutters to other bird species to chainsaws, kinda like that guy from Police Academy with the funny voices, only it can’t carry a gun.
This behavior is particularly common in captivity, where lyrebirds are inundated with decidedly unnatural sounds. And check out the second video below of a lyrebird in Australia’s Adelaide Zoo. It not only pulls off the din of a drill and hammer strikes, but the tone changes as a nail is driven home, guaranteeing that zoo employees will be annoyed by construction long after the construction itself is finished.
Physiologically, what could be driving this incredible mimicry? What makes the lyrebird so adept at impersonation? Well, according to behavioral ecologist Anastasia Dalziell of the Australian National University, we don’t really know yet. We can assume the lyrebird must have excellent hearing and memory, but what makes it so special biologically hasn’t been studied at length.
What we do know is that the lyrebird is a kind of songbird, producing sound with a vocal organ roughly equivalent to our larynx called a syrinx. (Syrinx, by the way, is Greek for “panpipe” and the name of a wood nymph who fled from the advances of Pan, who was a bit of a jackass. Beseeching assistance from water nymphs at a river’s edge, she was turned into reeds, which Pan chopped to pieces and fashioned into a flute. So … yeah.)
With lyrebirds, “it is true that their syrinx is slightly different in structure than most other songbirds,” Dalziell said in an email to WIRED. “For example, it has fewer syringeal muscles, but exactly how the structure of the syrinx allows it to produce so many sounds is not yet clear.” Strangely, notes Dalziell, having more muscles in the syrinx typically corresponds with greater vocal complexity — but the ultra-talkative lyrebirds (and parrots, as it happens) are exceptions to this rule.
In the wild, males will not only flawlessly imitate some 20 different species of birds, but multiple calls from each. They’re particularly fond of imitating Australia’s famous laughing kookaburras, and Dalziell has heard them mimicking the wing beats of small birds jetting through the forest understory. Up to 80 percent of a lyrebird’s song can consist of such mimicry, according to Dalziell, and “males imitate most often during the breeding season, particularly when females are fertile, so in this species there is strong evidence that for males mimicry is sexually selected.”
Commentaires