Eleven thousand reindeer once roamed the remote island of South Georgia and the Kerguelen Archipelago, but authorities have since decided to eliminate their populations. These reindeer were introduced to the islands in the early 20th century by Norwegian whalers and French scientists. They brought the animals to regions without natural predators, intending them as a local food source and for recreational hunting by workers stationed there. The first reindeer arrived on South Georgia in 1911, with more added in 1912 and 1925. On Kerguelen, reindeer were introduced in 1955 and 1956 to support isolated research stations, where no large mammals had previously existed. The absence of predators allowed the reindeer to multiply rapidly. By 1974, the population on Kerguelen’s main island, Grande Terre, had reached about 2,000. This growth led to the local scarcity of two native plant species, the Kerguelen Cabbage and the Azorella. Today, the Kerguelen herd fluctuates between 3,000 and 5,000 animals, putting continuous pressure on the island’s vegetation. On South Georgia, the reindeer population grew significantly after the last whaling stations closed in the 1960s. By 2013, estimates suggested several thousand reindeer were present, overgrazing the tussock grass that is vital to the coastal ecosystem. This overgrazing led to the loss of vegetation and negatively affected burrowing birds like prions and petrels. The overgrazing issue is not unique to these islands but is a result of reindeer biology when left unchecked. A similar case occurred on Saint Matthew Island in the Bering Sea, where 29 reindeer were released in 1944. By 1957, their population had grown to 6,000, but by 1963-1964, the population collapsed due to a harsh winter. This pattern highlights the risks of introducing non-native species to isolated environments. In response to the environmental damage, different approaches have been taken. South Georgia opted for a complete eradication, culled 1,012 reindeer, and recovered meat from 929, selling 7,685 kg of meat to cruise companies and restaurants in the Falkland Islands. Today, no reindeer remain on the island. In contrast, Kerguelen has chosen a more controlled approach, allowing the French herd to remain under surveillance rather than pursuing total eradication. This decision reflects differing strategies in managing invasive species and their ecological impacts.