A black-footed gray langur turns up twice near Jogeshwari West

A Malabar Sacred Langur (*Semnopithecus hypoleucos*) has turned up twice in the past month among the residential buildings of Jogeshwari West, on August 27 and again on September 2.¹ The two spots are less than a kilometre apart and roughly three and a half kilometres from the Aarey forest and the boundary of Sanjay Gandhi National Park.

This is a slim, long-limbed monkey with a long tail and long, silky fur that runs from cream through pale grey, sometimes with a wash of orange.² The face is a black triangle, the ears are black, and the hands and feet are black against the pale body; the name black-footed gray langur comes from that contrast.² The monkey Mumbai residents see far more often is the bonnet macaque, and the two are easy to separate. The macaque is stockier and grey-brown, with a bare pink face and a mop of centre-parted hair on the crown, and it spends much of its day on the ground picking up whatever it finds: fruit, leaves, insects, lizards, the odd egg. The langur stays mostly in the canopy and eats leaves. Telling this langur from the northern plains gray langur of central and northern India is harder, since the two were treated as a single species until recently and share the same build and grey coat. The differences are the darkness of the hands and feet and, above all, geography. From the Tapti River southward along the Western Ghats and the west coast, through Maharashtra, Goa and Karnataka into Kerala, the grey langur is this one.²

Leaves are a poor food. Mature foliage is mostly cellulose, which no mammal can digest on its own, and a fruit-eater's gut would pass it through nearly untouched. Langurs get around this with a greatly enlarged stomach divided into chambers, where bacteria ferment the leaf mass before it moves on, much as a cow's rumen does.² That gut lets a langur live on foliage that macaques and most other primates cannot use, with fruit and flowers taken when they come into season. It forages mainly in the trees but does come down to the forest floor. Young males leave the troop they were born into when they mature and join or form bachelor groups of non-breeding males.³

Mid-September, at the tail of the monsoon, is when Mumbai's canopy is at its fullest. Terminalia is carrying its tender new leaf flush, copperpod is in flower and setting pod, tamarind is ripening, and the peepal and banyan figs have finished their leaf flush and are heading toward a fruiting pulse that runs from October into December. For a leaf-eater, this is the month with the most to eat.

The species belongs to moist deciduous and riverside forest, sacred groves and gardens, mostly between about 100 and 1,200 metres.³ The two sightings are presence records and say nothing about how many langurs use the Jogeshwari edge or how often.¹ What they do show is a grey monkey with black hands, a black face and a long tail sitting in a canopy a few kilometres out from Aarey, and anyone who sees one here now knows what it is and what it is doing up there.