He looks worried but he looks like this all the time.
Sifakas are a genus (Propithecus) of lemur from the family Indriidae within the order Primates.
The name of their family is an onomatopoeia of their characteristic "shi-fak" alarm call.
Like all lemurs, they are found only on the island of Madagascar.
All species of sifakas are threatened, ranging from vulnerable to critically endangered.
Sifakas are medium-sized indrids with a head and body length of 40 to 55 cm (16 to 22 in) and a weight of 3 to 6 Kg (6.6 to 13.2 lb).
Their tail is just as long as their body, which differentiates them from the Indri.
Their fur is long and silky, with coloration varying by species from yellowish-white to black brown.
Sifakas move by vertical clinging and leaping - they maintain an upright position leaping from tree trunk to tree trunk and moving along branches.
They are skillful climbers and powerful jumpers, able to make leaps of up to 10 m (32.8 ft) from one tree to the next.
On the ground they move like all indrids with bipedal sideways hopping movements of the hind legs, holding their forelimbs up for balance.
Sifakas are diurnal, arboreal herbivores - eating leaves, flowers and fruits.
Reference: Wikipedia