Griffin (Kevin James) is a lovable loser working at the Zoo who can probably be found only in movies. He loves his job, is extra-nice to everyone generally, used to date a super-hot girl, Stephanie (Leslie Bibb) who dumped him when he proposed marriage to her & seems to have no ambition in life. Things move slowly and quietly for him, until Stephanie re-enters his life & seems to show interest in getting back. Griffin has no idea how to go about it but wait, the animals at the Zoo can talk & they want to help Griffin get the girl of his dreams. Thus they start to offer advice to Griffin in the ways of the wild about how to impress Stephanie. At the same time there is another, "simpler" (read less bitchy) love interest at the zoo, Kate (Rosario Dawson) who might be falling for Griffin too plus there is the subplot of Bernie (voice of Nick Nolte), a Gorilla with issues of animal abuse at the hands of another sadistic zoo employee, Shane (Donnie Wahlberg).
The movie chooses to play it loose and fast with most of the material resulting in a mess of plot that trudges along hoping the acting and voice talent involved will overcome the sub-standard writing. Thus we have Adam Sandler in a ridiculous accent trying to be a wise-ass, which oddly enough applies for nearly all the animals too; as if the only way animals are able to talk are in stereotypes.
The love story too lacks any real charm and if not for Rosario Dawson who brings some amount of radiance to her portrayal, I'd have hated it even more. Kevin James has been doing the same character arc for far too long and needs to break out of the mould. The voice talent might have the likes of Sly Stallone, Cher, Don Rickles, Maya Rudolph & even Judd Apatow but the only one who leaves any kind of impact is Nick Nolte as the scarred Bernie.
'Zookeeper' is a boring movie that lacks any real moments of humour and charm that might elevate the movie to watchable status. Id say avoid it, even the kids might not enjoy this one; a real trip to the zoo might be more fun.