By John Travis
Instead of eating fruits and insects as most monkey species do, colobine monkeys in Asia and Africa have a diet more like cows’. They don’t graze on grass, but they do ingest leaves. Two groups of biologists have found that evolution tailored one of the monkeys’ enzymes to this unusual leaf-eating diet.
Similar to cows, colobine monkeys fulfill their nutritional needs in an indirect way. Their diet of leaves lets bacteria thrive in their foregut. Downstream, in their stomach, the monkeys use enzymes called lysozymes to break open these bacteria and employ other enzymes to convert microbial proteins, DNA, and RNA into nutrients.