They have broad, dark-colored faces with wide, expressive eyes. They average between 13 and 14 pounds. Diet. Beyond leaves, red leaf monkeys also consume large amounts of seeds and flowers.

Since human genes were used and the monkeys' eyes and brains are similar to ours, at least in terms of color vision, the researchers hope the same procedure could work in humans.

Monkeys and their human cousins don't necessarily see the world the same way, ... green and red. 2:22. ... Smith devised his experiment to give the tamarins an eye-test.