Two wild-born adult Callimico males showed a skillful performance in killing a small eastern ribbon snake (Thamnophis s. sauritus); in both instances the snake was eaten; to date only capuchins (Cebus spec.) were known to kill and eat snakes. The killing action was very similar to the killing of lizards but differed from preying on frogs. This gives us evidence that small snakes may represent relationship a source of protein for some Callimico in the wild. At the same time a new aspect of the relationship between snakes and noahuman primates is indicated.