Reproduction
An infant gray gentle lemur peers from its mother's back. Click image for larger version.
Bamboo lemur females come into estrus once a year, typical for a diurnal lemur. Single infants, and very rarely twins, are born after a gestation of some 140 days, longer than average for a lemur. Infant care is highly unusual in this species. Rather than carry the infant, as is typical of most lemur mothers, or keep the infant in a nest, as ruffed lemur and aye-aye mothers do, the bamboo lemur mother does something else entirely.
From the day of birth the mother might "park" the infant on a small branch in the middle of the bamboo grove while she goes off foraging, returning periodically to groom and nurse the infant. The fact that the middle of a bamboo grove is a dense thicket protected from predators surely has aided in the evolution of this strategy. In captivity, the mother might park the infant on the side of a cage, a protective heat lamp basket, or a small branch. If the females need to transport the infant to another location, they do so by picking it up in their mouths and carrying it via this method. Mouth carrying is seldom seen after the infants get to be two weeks old, however, as by this age the infants are becoming surprisingly mobile and may not stay put if parked in a given location.
Infants older than a couple of weeks will also often hop onto the mother's neck and travel short distances thusly, but some mothers are extremely reluctant to transport their infants in this manner, and will nip at the infant until it hops off. In those cases, the mobile infant, especially when frightened, will simply jump onto the nearest group member, whether it is a sibling or its father. In fact, bamboo lemur juveniles and fathers play a more active role in infant care than is typical in lemurs. After a surprisingly short period of time, however, the infants are navigating around completely on their own.