Mary G. Thompson 
Escape from the Pipe Men! 

Thirteen-year-old Ryan Hawthorn has spent his life on display as a human exhibit in the multi-eyed Pipe Mens intergalactic zoo. When his father is accidentally poisoned, its up to Ryan and his seven-year-old sister, Becky, to scour the universe for the antidote. Along the way, they encounter many strange creaturesfrom the doglike Hottini to the spindly-legged, hairy Xaxorand learn that the Pipe Men (or, as Becky calls them, overgrown drainpipes) are not kindly overlords, as they had been led to believe. It’s not only the humans who are planning to rebel! A wildly imaginative middle grade space-travel adventure.