The male proboscis monkey has a pendulous nose that is thought to amplify his calls to females (and his warnings to big-nosed rivals). See it in Borneo (and the Singapore Zoo).
The aye-aye is a kind of lemur, with large round ears that rotate independently. The aye-aye feeds using its long middle finger to scoop out grubs in tree bark. See it in Madagascar (and the Bristol Zoo Gardens).
(Courtesy Bristol Zoo Gardens)
Almost totally blind, the naked mole rat is one of only two species of mammals that live in colonies with a caste system, like termites or ants. See it in Ethiopia, Kenya, and Somalia (and Zoo Atlanta and the National Zoo).
(Courtesy Jessie Cohen/Smithsonian\'s National Zoological Park)
The tiny Philippine tarsier's eyes are about twice the size of a human's and have no peripheral vision. See it in The southern Philippine islands of Bohol, Samar, Leyte, and Mindanao (and the Philippine Tarsier and Wildlife Sanctuary in Bohol).
The emperor tamarin's wildly eccentric moustache (strikingly similar to Mr. Monopoly's) is something of a mystery. Experts think it might be a unique identifier, as a fingerprint is for humans. See it in Bolivia, Brazil, and Peru (and the Paignton Zoo, in Devon, England).
(Courtesy Paignton Zoo)
The knobby, gnarled matamata turtle uses its huge mouth to suck in unsuspecting food sources as they pass by. See it in The Amazon River in Brazil, and in parts of Trinidad and Guyana (and the Honolulu Zoo and San Diego Zoo).
(Courtesy San Diego Zoo)
The red patch of skin on the female gelada baboon's chest gets brighter as her hormone levels increase. As a natural design feature, it's a little too much information. See it in Eritrea and Ethiopia (and the Bronx Zoo).
(Courtesy Bronx Zoo/WCS)
The unattractive Chinese giant salamander can grow to three feet long. Their meat is considered a delicacy in parts of China. See it in The streams and lakes of central China and Taiwan (and the Steinhart Aquarium in San Francisco).
(Courtesy Steinhart Aquarium)
The echidna is an evolutionary mashupit has a pouch for its young like a kangaroo, spines like a porcupine, and a sticky tongue like an anteater. Oh, and it lays eggs like a chicken. See it in Tasmania and New Guinea (and the Cleveland Metroparks Zoo).
(Courtesy Cleveland Metroparks Zoo)
The blue, turkey-size Victoria crowned pigeon has outrageous plumage and lives mostly on the ground, mating for life and building sturdy nests for their young. See it in New Guinea (and the Philadelphia Zoo).
(Courtesy Philadelphia Zoo)
White-faced sakis prefer to stay in the mid-level trees of the rain forest, where they can jump up to 30 feet in a single bound. See it in Northeastern Brazil, French Guiana, Guyana, Suriname, and Venezuela (and the Elmwood Park Zoo in Norristown, Pa.).
(Courtesy Elmwood Park Zoo)
The tree pangolin is an insect eater with scales that feel a little like human fingernails. But don't touch: Like the common skunk, the pangolin has an unpleasant-smelling spray for those who get too close. See it in Central Africa's rain forests (and the San Diego Zoo).
(Courtesy San Diego Zoo)
Pygmy marmosets communicate though whistles and twitters, but when hostile they emit a frightening cry that's audible to peers but inaudible to humans. See it in Brazil, Colombia, Ecuador, and Peru (and the Houston Zoo).
(Courtesy Houston Zoo)
Instead of swimming upright, like sea horses, the leafy sea dragon swims in a horizontal position and uses its mouth as a straw to suck up food. See it in The southeastern Indian Ocean, near southern and western Australia (and the Georgia Aquarium in Atlanta).
(Courtesy Georgia Aquarium)