Species series – Red Langur


The red langurs (or Kelasi as they are known here in Sabangau) are small primates that live in groups of 3 to 10 individuals that are made up of one male and many females. For the kelasi in Sabangau, more than 83% of their diet is fruit, which makes them frugivorous. However, they are quite selective about what they eat, preferring unripe fruit and seeds. They therefore have to spend a long time each day searching for this fruit and have the longest day-range of any folivorous primate. This means that our kelasi team who study this species also have the longest days of any of our primate research staff!

Kelasi eating leaf shoots – Sabangau –OuTrop – 2014
The kelasi are very easily recognisable because of their bright orange fur but they can also be identified by their distinctive calls. Larissa, one of OuTrop’s masters students from Jakarta, has studied these calls for the last 6 months and has found that they are much more varied than we previously thought.

Red langurs are endemic to the island of Borneo, which means that they cannot be found anywhere else in the world! Although currently listed on the IUCN’s Red List of Endangered Species as “Least Concern”, due to our lack of knowledge and the alarmingly high rate of deforestation on this island, it is vital that this assessment be reviewed and updated. OuTrop is working hard to understand the behavioural ecology of this species so that we can better understand their conservation needs.