"tchi-fak" vocalizations and growls varied by population, where a population subject to significant terrestrial predation associated these vocalizations with anti-terrestrial responses in which the sifakas looked down and climbed up, while another population associated the "tchi-fak" with a non-specific flight response, and the growl with mild disturbance. Reproduction Around 45% of females breed each year when in oestrous between late January and early February. Females give birth to one infant after a gestation period of 130 days, between June and August. For the first 6–8 weeks, the infant clings to the mother's stomach, but for the following 19 weeks, it clings to her back. About 30% of infants are lost to predation by the Fossa (Cryptoprocta ferox) and a smaller number to raptors like the Madagascar harrier-hawk (Polyboroides radiatus). Those that do survive reach sexual maturity between 3–5 years. Males generally leave the group to join a neighboring group while adult females tend to stay with their natal group. Ecology and conservation status The species is listed in CITES Appendix I, and its IUCN conservation status was updated to Critically Endangered in 2020. In the small spiny forest fragments of South Madagascar, sifaka abundance appears to be influenced by the proportion of large trees (diameter at breast height >=5 cm) and by the abundance of the plant species Allouadia procera, a key species of the spiny forest habitat. A long-term, large-scale demographic study of the species at Beza Mahafaly Special Reserve in southwest Madagascar found that the sifaka population there had a population growth rate of 0.98 (with confidence intervals spanning 1), suggesting that the population was not in danger of imminent extinction. However, both severe droughts and an increased annual variation in rainfall levels can depress the population growth rate. References External links ARKive - images and movies of the Verreaux's sifaka (Propithecus verr) Mongabay.com - Dancing lemur attracts tourists to island of Madagascar BBC facts Sifakas Mammals described in 1867 Madagascar dry deciduous forests Madagascar spiny thickets Taxa named by Alfred Grandidier