Indri indri (Gmelin, 1788)

Scientific name: 
Scientist name: 
(Gmelin, 1788)
English: 
Indri
Other english: 
None
French: 
Indri
German: 
Indri
Malagasy: 
Babakoto, Indry (Mananara), Endrina, Amboanala
Taxa: 

Species

Identification

Indri indri has a head-body length of 64–72 cm, a vestigial tail only 5 cm long, and a body weight that ranges from 6 kg to as much as 9.5 kg (Glander and Powzyk, 1998; Powzyk, 1997; E. E. Louis Jr., pers. obs.). The high end of the weight range makes it the largest of the living lemurs, but a big diademed sifaka (Propithecus diadema) approaches it in size. It is a typical vertical clinger and leaper, with long hind limbs compared to its trunk and forelimbs, and a preference for postures in which the trunk is held vertically. Coat color varies from predominantly black, contrasting with a white pygal patch and a broad, paler facial ring, to variegated black-and-white, the white areas corresponding to the occipital cap, a collar extending up to and beyond the ears, and the outer surfaces of the legs and lower arms (Groves, 2001). The ears are black, modestly tufted, and highly visible. The earliest indris to be described exhibited the darker color pattern, which is typical of museum specimens from Andapa and Maroantsetra, and has also been observed in wild populations from Anjanaharibe-Sud (Thalmann et al., 1993; R. A. Mittermeier, pers. obs.), Makira (D. Meyers, pers. comm.), Ambatovaky, and Anjozorobe (F. Hawkins, pers. obs.).

The indri is readily located and identified by its eerie wailing song, and is unlikely to be mistaken for any other sympatric lemur (Powzyk and Thalmann, 2003). It is easily distinguished from the similar-sized, lighter-colored diademed sifaka, Propithecus diadema, by its prominent ears, long muzzle and vestigial tail, which contrasts strongly with the long tail of all Propithecus species. Varecia variegata also has a black-and-white color pattern but has a long tail, moves quadrupedally, and is smaller.

In the Analamazaotra Special Reserve and in the Anjozorobe-Angavo Protected Area, the male indri is slightly larger than the female, but there is
no difference between the sexes in color pattern. Male and
female indris can be distinguished, however, by their wailing
song. Both sexes participate in the song in a coordinated
manner but they differ in the presence or absence of note
types, in the acoustic features of note types, and in the
number of notes emitted (Giacoma et al., 2010).