Otherwise, when the novelty wears off, rescues everywhere are going to have their hands full with surrenders,” Potsus said. A guinea pig can scare or startle easily and if a child doesn’t have a good hold, it will run off. "Guinea pigs can’t jump,” said Fenella Fpeece, president of Wee Companions Small Animal Adoption Inc. in San Diego. A fall, even from a sofa, will paralyze them, and then "they are probably as good as dead.” She is worried about the big plastic balls used in the movie and sold in pet stores. They are made for hamsters and mice, she said. "Guinea pigs don’t have flexible backs and they don’t go in wheels.” They also have delicate digestive systems. "Kids get distracted. If you forget to feed it, it’s done. Its little life is over,” Fpeece said. She has already been asked if she has a guinea pig that looks like one of the agents. And ads on Craigslist are offering "‘G-Force’ type guinea pigs. I am really worried,” she said. Activists say there are several waves of worry ahead: when the movie debuts, when it comes out on DVD and when the novelty wears off. About 795,000 homes have guinea pigs as pets, according to the American Pet Products Association. Volunteers from most guinea pig rescue groups will beef up opening weekend public education programs in an effort to prevent impulse buys, said Susan Lee, director and CEO of the Costa Mesa group. For "G-Force,” a statement will be posted on the movie’s Web site and on other promotional materials, advising viewers to be responsible and research any pet "to make sure that it is suitable for your particular situation” and consider adopting from a shelter.