hamsters, mine is never grumpy, he loves space, and is very active....JUST BE CAREFUL what wheel you get him, because if you get him some metal wheels they can break limbs if they stop suddenly in mid-run and for this reason i reccomend you get a crittertrail cage and a few extra tubes, PANDA BEAR hamsters are the best IMO i have had 5 hamsters and the dwarf hamsteres are horribley grumpy, while pandas are cute, big and usually live long, and are less likely to slither away also, if you hold a hamster correctly they wont slithery-di or slithery-do away they are black and white so they are cute too.