Male Lactation
The Dayak fruitbat, found in Malaysia, Borneo, and Sumatra, apparently has a feature unique among mammals - the males lactate. Scientists aren't quite sure why, but it might be in order to assist the female in nursing the young, or the result of eating plants with estrogen-mimicking compounds.
http://en.wikipedia.org/wiki/Dayak_fruit_bat#Paternal_Lactation
http://www.batcon.org/batsmag/v13n1-7.html