10 Really Great Animal Dads

Tamarin

2 of 11
tamarin monkey photo
2 of 11

When multiple births are the norm, it's not surprising that nature has made males more willing to pitch in. Twins, and even triplets, are common among the New World monkeys known as Callitrichidae -- marmosets and tamarins (pictured) -- and in both groups male members of each social unit do most of the work carrying the infants around, then passing them back to their mothers to nurse. Fathers also groom and feed older offspring.

Photo of golden lion tamarins in a zoo by Art G. via Flickr