In the wild, lesser Malayan mouse deer are commonly herbivores and folivores, eating leaves, buds, shrubs, and fruits that have fallen from trees. Reproduction Mouse deer can breed at any time of the year. The fawn is weaned for 10-13 weeks. It reaches sexual maturity at about 5-6 months. Some are solitary.
Mouse deer are very shy and try to remain unseen.
T. javanicus are most active during the night. The male mouse deer are territorial. Male mouse deer protect themselves, and their mates, against rivals by chasing or slashing them with their sharp canines. The mouse deer population is threatened by hunting and habitat destruction. One method to prevent the extinction of mouse deer is captive breeding.