Left behind for 200 years: The 'forgotten' pigs of Auckland Island are finally catching a break.

A little act of kindness can cast a very long shadow. In 1807, a sea captain left pigs on a distant island for the benefit of future sailors. More than two hundred years later, people are still arguing about the pigs of the Auckland Islands. In a 2022 paper in the New Zealand Journal of Ecology, Michael Trotter and Michael Willis reviewed how livestock arrived at these subantarctic islands south of mainland New Zealand and the fate of the pigs.

A captain's gift for castaways

Captain Abraham Bristow found the islands in 1806 but did not land. He returned a year later and stayed on the islands for two months. In 1810 he wrote a letter saying he had left a breed of hogs on Enderby Island for the benefit of future navigators. Livestock arrived on the islands to feed castaways or to be farmed, the study explains. Ships did wreck there, including the Grafton in 1864, and the General Grant in 1866. Survivors of the General Grant later caught pigs on Auckland Island.

The pigs weren't staying put. A United States expedition in March 1840 spent some days in the north of Auckland Island and saw no pigs. In November and December of that year, Captain James Clark Ross found many running wild there and left more. Ross believed the pigs were from Bristow's hogs, but the authors noted that this was not certain, since the animals may have swum over from Enderby Island. When the survivors of the General Grant were rescued, they turned their remaining pigs loose on Enderby Island for the benefit of others. Those pigs were dead or killed off by 1887, but the wild pigs on the larger Auckland Island itself survived.

The 1999 rescue and its medical value

Conservation officials called the pigs on Auckland Island a threat to the environment and planned to remove them. A rare-breeds group had already stepped in to save a living sample. The team left Bluff Harbour, on the southern coast of New Zealand's South Island, for the Auckland Islands on January 12, 1999. Trained dogs tracked the pigs through thick forest, and handlers taped the pigs' legs and jaws before carrying them to the shore. In the end, 17 pigs were caught on Auckland Island and taken to New Zealand. The authors mentioned their calm temperaments, and their tails generally ended in a tassel, while several had almost woolly ears. DNA studies showed they were a separate breed and closest in type to European pigs.

The rescue also had medical benefits. Samples from the pigs were sent to labs around the world and returned free of a virus that worried researchers studying pig-to-human transplants. The pigs were first studied as a possible source of cells to treat diabetes. The breed has been a valuable source of medical products, the study reports. But it is a small group. Neither the pigs in the biosecure facility nor those elsewhere in the country are likely to number more than 30 mature animals. A separate genetic study found low variability compared with other pigs.

Pigs that stayed behind

Wild pigs also stayed on Auckland Island. Stephen Horn and colleagues reported in a 2022 feasibility study that it was the only island in New Zealand's subantarctic region that still had introduced mammalian pests: pigs, mice and cats. They found that removing all three was worthwhile and feasible, but that it depended on further development of new technology. Decision makers delayed the work in 2020 because of the economic effects of COVID-19. The issue split people. Trotter and Willis wrote that the pigs do cause some environmental damage, but argued their human value could be of huge global benefit and their genetic material should be preserved. That left the island pigs both a medical resource and an environmental problem, depending on whom you asked.