I can think several mammals with five letter names. These would include the otter, the horse and the sheep.
zebra
Seal, sealion
Whales and walruses are two animals with names starting with the letter W.
Newfoundland and Norfolk terrier dogs and Narwhale whale are mammals. They begin with the letter n.
panda
bunnychickchimpeaglegoosehorsehoundhippokittyllamamousemoosepandaperchpuppyrobinrhinosheepsharksnakesnailwhaletigerzebra
liverpool
There are a few mammals with generic names beginning with the letter X. They include:Xerus - a type of ground squirrel from AfricaXenomys - a rat from MexicoA few mammals with common names beginning with the letter X are:Xenurus - a type of armadillo from South AmericaXanthippe's Shrew: Crocidura xantippeXantus - another name for the yak.The Xoloitzcuintli is another name for the Mexican hairless dog.The xaliney is a type of cat.There is also a group of mammals called the Xenarthra - they comprise armadillos, sloths and anteaters.
mammals
Radio Rango
Quagga and quokka are two. There really aren't that many mammals whose common names start with the letter Q.The Quagga, an extinct type of zebra which looks like a cross between a zebra and a horse.
Three U.S. states have five letter names. The states are Idaho, Maine and Texas.