Presbytis rubicunda | Maroon Langur
Possible spot: Gua Gomantong Caves, Sabah, Malaysian Borneo
Seeing this Species
I saw a group of maroon langurs well and clearly but briefly. Too briefly to get a good shot, so I'm not quite counting them as seen. We're still researching a good spot to see them, but these caves offer a possibility.
The caves themselves are also incredible. Locals harvest valuable swallows nest using incredible ladders.
Probability of Success: ◆ ◇ ◇ ◇ ◇