Living Creatures

A term used by Treebeard the Ent, reciting a rhyme of lore that named the Living Creatures of Arda. He claimed to have learned the lore when he was very young, which places it far back in the First Age and therefore ancient indeed at the time of the War of the Ring. The lore of the Living Creatures started with the four free peoples: Elves, Dwarves, Ents and Men, and then went on to list the animals of the world. We do not have the full rhyme, but we do know that it included at least bears, beavers, boars, deer (separated into bucks and harts), eagles, hares, hawks, horses (at least in passing), hounds, oxen, serpents and swans.

There were several obvious omissions from the old list of Living Creatures, most notably the Hobbits, who apparently emerged after the rhyme was created. They later gained their own line in the rhyme, coined by Peregrin Took. It is perhaps notable that no Orcs, nor any of the apparently sentient creatures of the Dark Lord, are mentioned in Treebeard's rhyme of lore, at least so far as we know.

The term 'Living Creatures' seems to be broadly equivalent to Elvish kelvar, living things that could move, though it's not entirely clear whether an Elf would have considered one of the free peoples to belong among the kelvar (while they were clearly counted among the Living Creatures).