Sometimes you just need to borrow an animal — nothing else will scratch that fluffy-furry-squeaky itch except temporary ownership. Thank goodness for Sulphur Creek Nature Center in Hayward. For just $15, you, too, can take home an animal for a week — a guinea pig, say, or a rat, or a hamster, or a mouse. The center provides a cage, food, a bowl and water bottle, and a care sheet. And animal rentals are just the beginning at Sulphur Creek: The facility boasts a wildlife rehabilitation center as well, in which staff care for rescued animals that can't return to the wild because of injury, including owls, eagles, hawks, foxes, coyotes, and snakes. Then there are also wildlife education classes led by naturalists or docents — interactive programs with live amphibians, reptiles, birds, mammals, and arthropods. Who knows? If you ask politely, you might be able to hold a tarantula or feed meal worms to the chickens. Just make sure to wash your hands before you load your borrowed rat in the car.