The rare sequel that improves on the original, “Madagascar 2” keeps the silliness and steps up the heart. In the first film, four zoo animals run away and after a series of adventures are sent to live in an African wildlife refuge. Alex the pampered city lion (voice of Ben Stiller), Marty the zebra who longs for the veldt (voice of Chris Rock), Melman the hypochondriac giraffe (voice of David Schwimmer), and Gloria, the warm-hearted hippo (voice of Jada Pinkett Smith) are still, so to speak, fish out of water when it comes to living in the wild. Alex especially is eager to get back home. But their plane, piloted by ditsy penguins, crashes and they find themselves again in the wilderness.

But this time, it feels like home. Alex is reunited with the parents he barely remembers (voices of Bernie Mac and Sherri Shepherd). Marty is overjoyed to be at last among his own kind with a herd of zebras. Gloria wants to settle down with a mate and is delighted to see some handsome hippos as possible prospects. And Melman’s expertise with medical treatment gets him dubbed the new witch doctor. He is able to save the life of a young giraffe by setting his broken leg.

But a rival for the “alpha lion” position (voice of Alec Baldwin) tricks Alex’s father into forcing Alex to fight and banishing him when he loses. Marty finds that while the other zebras may look and act exactly like him, he misses his best friend. Melman tries to find a way to tell Gloria how much he cares for her. And Alex has to find a way to be true to himself as a lion and as a New Yorker.

While there is nothing as tone-deaf as the first film’s focus on whether Alex would eat his best friend, there are still a few clangers. Though gently handled, part of the plot concerns a character’s offer to sacrifice himself by jumping into lava because some of the animals believe it will appease the gods and restore their water supply. A cub is captured by poachers and his father is shot (minor injury). A feisty elderly woman’s fistfights are intended to be humorous. There is nothing especially new here. But it is funny and colorful and even a little bit sweet and you gotta love those nutty penguins.