IN THE first occurrence of its kind in a wild species, scientists report that fruit bats males (Dyacopterus spadiceus) occasionally lactate. Till now, this oddity was seen only in humans and domesticated animals (Nature, Vol 367, No 6465).

Jennifer A Brunton and Thomas H Kunz of Boston University and their colleagues who studied the fruit bats in the Krau Game Reserve in Malaysia, suspect that the mammary glands of these bats contain an enzyme that converts testosterone into oestrogen -- a hormone that excites milk secretion.

Another theory says male lactation is most likely to evolve in monogamous species, in which males also tend their young.