critter

Small or merely cute, creatures. Generally used to describe living creatures that are smaller than beasties, but larger than microbes. Usually when the speaker is unsure or uncaring of the species it belongs to.

A colloquialism referring to any animal. It's primarily used in America and Ireland. It's what's known as a pronunciation spelling of "creature" -- in fact, it probably dates back to the 16th and 17th centuries or before, when the "-ture" suffix was still pronounced without the "ch" sound.

Some critters include the cougar, the coyote, the grouse, the horse, the water buffalo, the mosquito, the sheepdog, the rattlesnake, the bobcat, the deer, the Siamese cat, the longhorn, the canary, the rat terrier, the roadrunner, the hoop snake, the field mouse, the chicken, the alligator, the sheep, the fox, the brown recluse, the kestrel, the moose, the rabbit, the beagle, the rabbit, the swan, the pig, the zebu, the pit bull, the owl, the gopher, the preying mantis, the donkey, the caribou, the plover, the vampire bat, the duck, the scorpion, the bison, the hound dog, the trout, the ostrich, the earthworm, the giraffe, the cobra, the finch, the elk, the ox, the jellyfish, the poodle, the camel spider, the heifer, the snipe, the crocodile, the penguin, the dachshund, the honeybee, the yak, the jackalope, the mandrill, the killer whale, the sparrow, and the werewolf.

Some research dug out of www.dictionary.com

A critter, to railfans, is a small locomotive, which can be either narrow or standard gauge, but more importantly must be quite tiny indeed. A critter would never pull something that could properly be called a train; a few cars, no more than half a dozen, would probably be its limit. A critter would rarely be hauling anything from place to place; the critter's domain was and is generally in one place, a rail yard or industrial plant, pottering around moving cars from building to building or making up and breaking down trains that arrive and depart under the control of larger power.

Critters are switchers in US parlance, or shunters in British, but there are switchers that are not critters. Switchers can, after all, be quite large; there were and are switcher designs that are larger than smaller road locomotives. It would be rare to call a locomotive of over 100 tons a critter, and generally they're a lot smaller.

Few of these locomotives were ever owned by real railroads -- the vast majority belonged (and in much smaller numbers still do) to industrial operations. Railroads might sometimes own one or two for use in very confined spaces, dockside lines or street railroads in industrial areas.

As originally conceived, the word was applied only to internal combustion engined industrial switchers -- gasoline or diesel powered -- but many would also count similarly diminutive electric or steam locomotives.