They are the same species, Rangifer tarandus. In Europe and Asia they are called reindeer; in North America, wild ones are called caribou. Domesticated animals are called reindeer everywhere, including in North America — so the split is partly geographical and partly about whether the herd is wild or herded.
The core difference
One animal, two names, divided by geography and domestication rather than biology.
- reindeer — the name used in Europe and Asia, and for domesticated herds anywhere.
- caribou — wild North American populations.
Why it is not a clean split
Because domestication cuts across geography. Herded animals in Alaska are reindeer; wild animals in the same region are caribou. The distinction tracks the relationship with people at least as much as the map.
A detail worth knowing
This is the only deer species in which females regularly grow antlers. Males typically shed theirs in early winter, while females keep theirs through to spring — which has produced the frequently repeated observation that a team of antlered reindeer in December would have to be female.
The words
Reindeer is from Old Norse hreinn, the animal, plus deer — so it is not "rein" as in reins. Caribou comes through French from the Mi'kmaq language.
Frequently asked questions
Are caribou and reindeer the same animal?
Yes, the same species. Reindeer is used in Europe and for domesticated herds; caribou refers to wild North American populations.
Do female reindeer have antlers?
Yes. It is the only deer species where females regularly grow them, and they keep theirs later into winter than males.
Does reindeer come from "rein"?
No. It is from Old Norse hreinn, the name of the animal, plus deer — nothing to do with reins.