Why Roosters Have Wattles

A wattle is the bit of flesh below a rooster’s beak. What purpose does it serve? Carolynn Smith at Macquarie University in Australia conducted a study that suggests that it’s pure chicken bling. Sarah Zielinski writes in Scientific American about the results:

Cutting off the wattles of roosters and seeing how the behavior of hens changed wasn’t an option. Instead, Smith created four animated roosters. The animated roosters (see second part of the video below) all acted the same, performing the tidbitting routine over and over, and they all looked the same, except for their wattles. One had a normal wattle, one was missing his, a third had a wattle that didn’t move, and the fourth had an extra floppy wattle.

A test chicken would be placed inside a test pen with two “audience hens,” a couple of buddies intended to make the test hen more comfortable in the less familiar surroundings (fowl are social creatures). One of the videos was then played for the test chicken and her response was recorded: How quickly did she respond to the animated rooster? How quickly did she start searching for food (the normal response to a male tidbitting)? And how long did she search for food?

The test hens responded more quickly to the tidbitting males that had the normal or stationary wattles, less quickly to the one with the extra floppy wattle (the wattle moved so much that it swung up the side of the rooster’s head and appeared much smaller than it was) and slowest to the male lacking wattles. After the hen’s attention was gained, though, she reacted about the same to each of the four animated chickens. Smith suggests that the wattle helps a rooster gain a hen’s attention when he is tidbitting, rather like a human guy wearing flashy clothes while doing his best dance moves to try and pick up chicks.

Video at the link.

Link | Photo: U.S. Department of Health and Human Services