The peacock is one of the animal kingdom’s ultimate Casanovas. But which parts of the peacock’s love dance turn a female’s head? An eye-tracking study finds it’s not what you might think.
Researcher Jessica Yorzinski of UC Davis and Duke University uses tiny custom-fitted cameras modeled after human eye-tracking devices to study peacock courtship from the female’s point of view.
A peacock’s long technicolor tail may be eye-catching, she said, but males have other amorous charms that could also get a girl’s attention.
“Females could be looking at the males’ eyespots, head crests, spurs, or the length of their legs,” Yorzinski explained. “For a bird that’s a textbook example of sexual selection, there’s still a lot of uncertainty about how females choose their mates.”
In other words, what’s hot to a peahen?
To find out, Yorzinski performed an eye-tracking experiment on twelve female Indian peacocks (Pavo cristatus) while males pranced and strutted.
Yorzinski showed me a video of two males vying for the affection of a female in an outdoor enclosure in Durham, North Carolina, where she conducted her experiments.
The female wore two miniature cameras mounted onto a custom-fitted cap that looked like a tiny aviator helmet. One camera pointed outward to record the scene in front of her. The other camera recorded her eye movements as she surveyed the scene.
Just a few feet away, a brilliant blue-green male lifted his tail into a giant semi-circular fan and rattled his feathers. Dozens of eye spots quivered and shimmered. He stepped side to side, and forward and back. Then he whirled around to show off his ruffled black-and-white backside.
The cameras on the female’s head were connected to a wireless transmitter that sent the video signals to a computer, which then translated the female’s eye movements into coordinates on a screen.
Yorzinski showed me video of the female’s gaze, with a yellow dot on the screen indicating the peahen’s shifting focus. The female glanced at the parading male, then she spotted a squirrel darting by, her eye continually bouncing back and forth.
Duke University PhD candidate Jessica Yorzinski built a two-camera eye-tracking system on tiny headgear to see what a peahen is looking at when the peacock fans out his elaborate tail in a mating display. Her study appears in the Journal of Experimental Biology, July 24, 2013.
By analyzing the videos frame by frame, Yorzinski was able to figure out exactly where the peahens looked at each moment. Surprisingly, females spent less than one third of their time looking at their suitors.
It could be that it simply doesn’t take a female long to tell a hunk from a loser, said biologist Adeline Loyau, a specialist in peacock mate attraction who wasn’t involved with the research.
“…Humans can tell in a fraction of second, when we meet a very attractive person, that the person is highly attractive, without having to stare at the person for a long time,” Loyau said.
When the females did look at the males, they looked the longest at the males’ legs and the base of their giant semicircular tails, and barely glanced at the upper parts of the males’ tails or their heads.
By scanning the lower parts of a male’s tail, females may be sizing up the width or symmetry of his train —the former being a sign of a mature male, Yorzinski explained.
Even if females pay little attention to the males’ upper tail feathers, these regions may still help males flag females from afar in the dense trees and shrubs that peacocks call home, she said.
Dance moves were important too. Yorzinski found that females looked the longest when the males were shaking their wings and rattling their tails.
This study doesn’t tell us whether males who get the longest looks are more likely to get lucky, Loyau added. For example, previous research by Loyau and others showed that male peacocks with more eyespots are more likely to get the girl.
Yorzinski’s results appeared in the July 24 issue of the Journal of Experimental Biology.
Yorzinski, J., G. Patricelli, et al. (2013). “Through their eyes: selective attention in peahens during courtship.” Journal of Experimental Biology, 216, 3035-3046.