Sara Gruen winningly demonstrated in her beloved best-seller Water for Elephants that she has a way with animals. The novel's romance might have been a little undercooked, but her descriptions of its real stars, the big-top elephant Rosie and the circus itself, were marvelous. And so it is here in Ape House, the tale of a delightful family of bonobo apes a highly sensitive and communicative species and the humans who alternately threaten and advocate for them. Gruen introduces her reader to these endearing animals, and then promptly inflicts some explosives on the Great Ape Language Lab, injuring scientist and bonobo lover Isabel Duncan in the blast. It's a propulsive beginning, and Gruen writes with the commercial breathlessness of a cozier Dan Brown. The pages turn, the twists abound, and the poor bonobos are suddenly sold off and forced into becoming the unwitting stars of a reality TV show.
Gruen, at her best in her affectionate depictions of the apes' sophisticated interactions with the world around them, once again falls flat when it comes to her two-legged creations. Isabel is likable enough, but other than some offhand background about an alcoholic mother and her own obsession with orderliness, she remains a sketch of a character. Journalist John Thigpen, who earned the bonobos' approval in an interview just hours before the bomb went off, is perfectly fine company. But his relationship with his tedious wife ''there was nothing he wouldn't do for Amanda. If she needed his liver, she could have it'' and his wishy-washy hesitation about having a baby are a drag on an otherwise zippy plot. (Would that Gruen had centered the action instead on supporting character Celia, a tattooed young grouch of a lab intern with genuine wit.) Still, the chapters are brisk and the action is swift. Whenever one of the humans starts to bore, you can be sure that a charming bonobo will quickly come to the rescue. B