It was tough competition but the male marmoset has been named top of the "pops" in a Father's Day survey.
Geoffroy marmosets are under threat
The tiny South American monkeys usually father twins or triplets and spend hours cleaning their babies and carrying them on their backs.
They are only returned to their mother for nursing and once they can eat solids, the father feeds them instead.
The poll among staff and volunteers at London Zoo and Whipsnade Park ranked marmosets ahead of seahorses and rheas.
The Zoological Society of London's curator of mammals, Malcolm Fitzpatrick, said: "Marmosets are amazing animals that tend to live in family groups.
"The males are heavily involved in the rearing of infants which makes them a worthy winner."
Oriental short-clawed otter
Von der Decken's Hornbill
Bangaii cardinal fish
He said the Geoffroy marmoset was threatened in the wild from habitat destruction, and London Zoo was aiming to conserve them.
Named second in the poll were male seahorses which become pregnant when a female deposits her eggs into his pouch.
In third were rheas, large ostrich-like birds from South America which take sole care of their young from eggs to chicks.