Karen McComb of the University of Sussex and her team recorded the purrs of 10 different cats when they were soliciting food, and when they were purring in a different context — and they found that hungry cats mimic a baby’s cry:
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.