Hungry cats dupe owners with acoustic trick

http://www.newscientist.com/article/mg20327175.700-hungry-cats-dupe-owners-with-acoustic-trick.html

Hungry cats dupe owners with acoustic trick
15 July 2009

Magazine issue 2717.

CAT owners will know the feeling. Your pet is demanding to be fed, and isn't going to give up until it gets what it wants. What most doting owners won't realise is that the cat is using an acoustic ruse.

According to Karen McComb of the University of Sussex, UK, domestic cats hide a plaintive cry within their purrs that both irritates owners and appeals to their nurturing instincts.

The team recorded the purrs of 10 different cats when they were soliciting food, and when they were purring in a different context. Fifty people who were asked to rate the purrs on how pleasant and urgent they sounded consistently rated the "solicitation purrs" as more urgent and less pleasant. Cat owners were especially good at distinguishing between the two kinds of purring.

When the team examined the sound spectrum of the solicitation purrs they saw an unusual peak in the 220 to 520-hertz frequency range embedded in the much lower frequencies of the usual purr. Babies' cries have a similar frequency range, 300 to 600 hertz, McComb says.

The louder this high-frequency element, the more urgent and less pleasant the purr was rated (Current Biology, DOI: 10.1016/j.cub.2009.05.033). Cats may be exploiting "innate tendencies in humans to respond to cry-like sounds in the context of nurturing offspring", McComb says.