Hungry house cats use an annoying but irresistible combination of sounds when they want to be fed, a new study has found.

The combo may explain why cat owners seem willing to fill food dishes at all hours rather than simply ignoring or ejecting the cat, noted study leader Karen McComb, a mammal-communications expert at the University of Sussex in the U.K.

When they're hungry, some cats blend their normal, pleasant purrs with whines comparable in frequency to the distress cries of human infants.

"They can sort of get away with solicitation that way rather than with just meowing, which might get them swept aside," McComb said.

The concept of cat purring is strange by itself, McComb pointed out.

"Cats shouldn't really be able to