Unexpected Surili opportunity

It was fortunate that I decided to check out the sounds of jumping and swinging, and falling twigs and leaves.  It turned out to be a group of White-thighed Surilis, a species of the Leaf Monkeys.  They are also known as Pale-thighed Langurs, taking their name after the whitish fur on their legs.  My previous encounter in the bukit with these monkeys were that they were very shy, watching from atop trees and moving on when spotted, unlike the more aggressive Macaques.  Thus I was pretty lucky when these few spotted were very much preoccupied, and those that were not, did not take off immediately when they spotted me.

This was the first one that I spotted and it went on chomping on what I could make out to be young leaves even when I was photographing it although it spied me, but it did move on eventually when I tried to get closer for my shots.
It's interesting to learn that these primates have multi-chambered stomachs to help in digestion of leafy matters and for toxins to be neutralised.

Close-ups of the beautiful Surili and its fine fur.

Its distinct dark tail was so long I couldn't fit it into my usual bird portrait shot.

Meanwhile a couple were seen lazing about.

My prized images would be of this adult and young.

A typical monkey moment as the young bit into the adult.

We could take a lesson or two from these two how to slump and de-stress, that is until one spotted me.

I felt that I was intruding when this one saw me and I did quickly move on, leaving the group alone, grateful that I had such an extended time getting precious images of this shy species.

Some facts/extracts on this species:

1. The white-thighed surili is classified as Near Threatened (NT) on the IUCN Red List and is listed on Appendix II of CITES (Convention on International Trade in Endangered Species).

2. The white-thighed surili lives in a variety of different forest types, including forests in lowlands and hills, swamp and lowland wet forest, and even disturbed areas such as plantations and orchards ... The loss of extensive tracts of forest in Southeast Asia poses a significant threat to the white-thighed surili.

3. ... the white-thighed surili (Presbytis siamensis) is a medium-sized, slenderly built monkey with a long tail, a short muzzle and relatively long fur. The top of its head and its back tend to be a dark greyish-brown, while the underside of the body, including the undersides of the tail, legs and arms, tends to be a lighter pale grey to white. There is also a large whitish patch on the outside of the legs, from which the white-thighed surili gets its name. The hands, feet, and outer half of the white-thighed surili’s tail are black.

The white-thighed surili’s face is characterised by poorly developed brow-ridges and indistinct pale rings around the eyes, with the rest of the facial skin being dark grey to blackish ... there is a crest of fur on the head.  Infants are lighter in colour than the adults, with just a dark cross-shaped pattern up the back and across the arms.

4. ... the white-thighed surili is a diurnal forest dweller, with a diet consisting of leaves, flowers, fruit and seeds. The proportion of fruit and seeds in its diet is quite high compared with most other species in its genus.