The Crozet Islands are a sub-Antarctic archipelago of small islands in the southern Indian Ocean.
The islands are part of the Southern Indian Ocean Islands tundra ecoregion that includes several subantarctic islands. In this cold climate, plant life is mainly limited to grasses, mosses and lichens, while the main animals are insects along with large populations of seabirds, seals and penguins.
The Crozet Islands are home to four species of penguins. Most abundant are the macaroni penguin, of which some 2 million pairs breed on the islands, and the king penguin, home to 700,000 breeding pairs; half the world's population. The eastern rockhopper penguin also can be found, and there is a small colony of gentoo penguins. There is also an endemic subspecies of the duck Eaton's pintail. Other birds include black-faced sheathbills, petrels, and albatross, including the wandering albatross.
Mammals living on the Crozet Islands include fur seals and southern elephant seals. Killer whales have been observed preying upon the seals. The transient killer whales of the Crozet Islands are famous for intentionally beaching themselves while actively hunting the islands' breeding seal population. This is a very rare behaviour, most often seen in the Patagonia region of Argentina, and is thought to be a learned skill passed down through generations of individual orca families. These killer whales also seem to stay around the Crozet Islands year-round, feeding on mostly seals during the summer, and then feeding on penguins for the winter.
The Crozet Islands have been a nature reserve since 1938. Introduction of foreign species has caused severe damage to the original ecosystem. The pigs that had been introduced on Île des Cochons and the goats brought to Île de la Possession—both as a food resource—have been exterminated.
Another on-going concern is overfishing of the Patagonian toothfish, as well as the albatross population, which is being monitored. The waters of the Crozet Islands are patrolled by the French government.