India, Oct. 23 -- 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.

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 isl...