Abstract
Douc langur (Pygathrix n. nemaeus or Pygathrix nemaeus) is kept in captivity outside ofAsia rarely. Due to the Vietnam war (the usage of Agent Orange), deforestation, and hunting, their numbers in the wild have been declining as well.
The langurs have adapted gastro-intestinal tract to digest food with high contents of undissolvable cellulose, however, they still do prefer easily digestible young leaves. All Colobinae monkeys have a stomach consisting of three to four compartments with bacteria specialized to decompose leaf cellulose, characteristic is also the buiId of their molar teeth, allowing for effectively chewing the leaves into sort of a "mash," The specific metabolism has a significant impact on their behavior, as well as on the diet regimen in the zoo, Due to the way they digest food, the langurs have a bulged stomach and burp often.
The difficulties tied to their demanding dietary requirements are the key reason íor the relatively unsuccessful history of being kept in captivity outside of Asia. At this moment, the Red-shanked doucs outside of Asia are: in 2.1. in Zoo Chleby, or 0.1 in Philadelphia Zoo, and 1.0 in Cologne Zoo.