The Reindeer

Reindeer are passive mobs that spawn in cold biomes and can walk normally on ice; unlike players and most other mobs—which slide on ice, making it difficult to turn or stop (though this allows for faster movement, such as by boat)—reindeer walk without sliding, just as they would on ordinary blocks. Defeating a reindeer yields no drops. Reindeer are sometimes targeted as prey by polar bears and are attacked by them. However, if a reindeer is attacked by a player, a polar bear, or something similar, it may quickly flee. Additionally, reindeer move in herds of four, and they breed using sweet berries. Much like putting a saddle on a pig, you can equip a reindeer with a carpet without needing to tame it first; while you cannot ride or steer them as you would a llama, they do move in herds, so if you equip the whole herd with carpets and lead just one with a leash, the rest of the herd will follow along behind. Incidentally, if you attach a boat to a reindeer with a lead, you can have it pull the boat; this suggests that reindeer could potentially serve as a new mode of transportation (if you have an entire herd of up to four reindeer pull the boat, it might effectively function like a sleigh).