According to a new study, the four-striped grass mouse (Rhabdomys pumilio) is certainly not fond of his neighbors during the breading season. Breeding males are much more concerned about repelling their neighbors than defending their partners from complete strangers.

Carsten Schradin from the University of Zurich, Switzerland, worked with a team of researchers to stage encounters between wild mice in a specially created ''''neutral'''' arena.

"We found that breeding males tested during the breeding season showed significantly more aggression towards their neighbors than towards strange breeding males not neighboring them. Breeding males were significantly more aggressive than non-breeders," he said.

This ''''Nasty Neighbor'''' phenomenon has been seen in other animals and contrasts with the ''''Dear Enemy'''' behavior in which the breeding male will preferably attack strangers.

The researchers, in this field study, were able to test the paternity of offspring conceived during the study period and found that neighboring males were more likely than the wandering strangers to sire pups with another mouse's ''''harem''''.

Schradin believes this may explain the animal's preference for neighborly aggression.

"We've found that the neighbors of breeding males pose a recognizable threat to the breeding male's confidence of paternity, and suggest that this explains the occurrence of the nasty neighbor phenomenon in striped mice," he further added. (With Inputs from Agencies)