At the Central Park Zoo, Marty the zebra (Chris Rock) is celebrating his tenth birthday, but longs to see the rest of the world from outside his pampered life at the zoo. Believing that he can find wide-open spaces to run around in, in Connecticut, he gets some tips from the zoo's penguins Skipper (Tom McGrath), Kowalski (Chris Miller), Rico (John DiMaggio), and Private (Christopher Knights). The penguins are similarly trying to escape the zoo. Marty's friends, Alex the lion (Ben Stiller), Melman the giraffe (David Schwimmer), and Gloria the hippopotamus (Jada Pinkett Smith), realize Marty's folly and try to follow him. The four, along with the penguins and the chimpanzees Mason (Conrad Vernon) and his silent friend Phil eventually find themselves at Grand Central Station, but are quickly sedated by tranquilizer darts when Alex's attempt to communicate is mistaken for aggression. The zoo (under pressure from animal-rights activists) is forced to ship the animals, by sea, to Kenya. During their travels, the penguins escape from their enclosure and take over the ship, intent on taking it to Antarctica. Their antics on the bridge cause the crates containing Alex, Marty, Melmen, and Gloria to fall off the boat and wash ashore on Madagascar.