Crowned lemurs are the most noticeably sexually dichromatic lemur species, with the exception of the blue-eyed lemur. The females are predominantly gray with an orange crown, while the males are a much darker reddish brown with a black and orange crown. Until recently, crowned lemurs were thought to be a sub-species of the mongoose lemur.
The crowned lemur is a mostly diurnal lemur with a very limited range in the northern tip of Madagascar. This lemur weighs, on average, about 1700 grams 1.7 kg. (3.4 lbs.), making it the smallest member of the Eulemur genus. Crowned lemurs are sympatric throughout most of their range with Sanford’s lemur(Eulemur fulvus sanfordi).
Although the diet of crowned lemurs varies with the seasons, it contains a high percentage of fruit with relatively few leaves. During both wet and dry seasons, fruit comprises as much as 80% to 90% of the crowned lemur diet. They prefer drier forests, existing in higher densities in these habitats than in adjacent humid forests. In fact, the crowned lemurs may be found in the more humid areas only because they have been forced out of their preferred dry habitat by human interference. Crowned lemurs generally feed lower in the forest than Sanford’s lemurs, which may help avoid aggressive interactions between these two species. Crowned lemurs often forage in scrubby bushes and short trees, and routinely come to the ground. In dry areas, the animals may venture deep into caves in search of water.
At the DLC, crowned lemurs are held in small family groups, usually consisting of an adult pair, their infants (twinning is fairly common in this species) and any juveniles from the previous year or two. Births at the DLC occur April through mid-June (mid September through October in Madagascar), with gestation being about 120 to 128 days. Births in Madagascar coincide with the start of the rainy season. Singletons and twins appear to be equally common. Infants are initially carried on the mother’s belly, but switch to her back when they are a couple of months old. Sexual maturity is estimated to be reached at around 20 months of age. It is not known if the presence of juveniles in a group during birth season or breeding season has an effect on either the production or survival of infants.
In the wild, crowned lemurs travel in all levels of the forest, but seem to prefer the canopy level. They readily descend to the ground to eat fallen fruit, lick or eat dirt, or travel. The animals are found in groups ranging in size from five to up to 15 animals (groups of five to six are the norm), with adults of both sexes present. Although the animals are more active during daylight than night, researchers have found that there is usually a nighttime activity period lasting up to two hours.
Large groups often break up into foraging subgroups of one to four animals. Such subgroups use vocalizations to maintain contact with, or to locate other subgroups when separation distances are large. Such vocalizations, best described as “piercing yaps,” can often be heard between captive groups at the DLC. Interactions between groups of crowned lemurs in the wild are rare, but aggressive interactions between crowned and Sanford’s lemurs have been reported. The home range of crowned lemurs is small, and there is usually significant overlap between the home ranges of neighboring groups.
Habitat and Conservation
The area of suitable habitat remaining in Madagascar for crowned lemurs is probably less than 1300 square kilometers in the far northern tip of the island, and this is shrinking rapidly due to the encroachment of slash and burn agriculture. Total population estimates range from 1,000 to 10,000 animals. As populations of this lemur become more and more patchily distributed in forest fragments, genetic interchange between the fragments becomes increasingly difficult or impossible, thus increasing the likelihood for extinction. A number of crowned lemurs have been released on the small, uninhabited island of Nosy Hara, but their status is unknown.
Four reserves in Madagascar protect the crowned lemur; however, even in the reserves, the animals are hunted by the local people for food (they are also popular as pets), as the borders of the preserves are poorly guarded. In one reserve, Montagne d’Ambre National Park, poaching of crowned lemurs and the sympatric Sanford’s lemur is widespread and growing. Like most lemur species there is a strong need for biological surveys to be undertaken to determine this lemur’s distribution, and for more reserves to be created. In one area, near Dariana, crowned lemurs are sympatric with the golden-crowned sifakas, and the creation of a reserve here would aid in the protection of both species.
The Lemur Center currently houses 6 males and 5 females in three breeding pairs. Recent births include a singleton and set of twins in 2013 and a singleton in 2010.