A gift of two pigs to Māori by a French explorer in 1769 marked an early chapter in the introduction of pigs to New Zealand, where the animals eventually spread through trade, breeding and escapes into the wild. Centuries later, their descendants remain part of the country’s landscape, raising questions about their impact on native wildlife and forest ecosystems.
According to historical accounts, French explorer Jean François Marie de Surville presented two pigs to Māori in Doubtless Bay, in northern New Zealand, in 1769. Before the arrival of introduced species, New Zealand had no land mammals apart from bats, making the introduction of animals brought by European explorers a significant development.
The fate of the two pigs gifted by de Surville remains unknown. However, pigs were subsequently introduced by other European explorers and settlers, and some escaped or were released into the wild. These animals bred and established feral populations across parts of the country.
Wild pigs in New Zealand are sometimes known as “Captain Cookers”, although the animals’ origins vary and not all feral populations can be traced to a single introduction. Pigs also became an important part of trade between Māori and Europeans. Historical accounts record several introductions during the late 18th and early 19th centuries.
Governor Philip King of Norfolk Island, for instance, provided pigs to Māori leaders, including Tukitahua and Te Pahi. Between 1804 and 1805, 56 pigs were transported to Te Pahi aboard three ships. The animals soon acquired considerable economic value. Māori traded pigs with Europeans from the early 19th century, and the scale of the trade grew over time.
Historical records indicate that during the 1840s, a horse could cost around 40 pigs, while a schooner could be exchanged for as many as 500 pigs by Māori in the Bay of Plenty.
Alongside their growing role in trade and food supplies, feral pigs became firmly established in New Zealand. By 1840, wild populations were well established, and pigs became the first introduced animals in the country to be hunted for sport. Their widespread presence later earned New Zealand the nickname “Pig Islands” among Australians. Pig hunting continues to be popular, with historical accounts recognising at least 25,000 pig hunters in the country. However, the ecological consequences of the animals’ spread are more complex than their reputation as invasive species might suggest.
A 2015 study published in the *New Zealand Journal of Ecology* examined the effects of wild pigs on the Waitutu Forest in South Fiordland. Researchers led by John Parkes studied soil disturbance, seedling growth and the stomach contents of 14 pigs killed by hunters over a period of 25 months. The study found that pigs disturbed between 7.4% and 12.4% of the soil on forest terraces at any given time.
They also repeatedly returned to previously disturbed patches, digging up older sites about seven times more frequently than newly disturbed areas. Stag beetles were a major target of their digging and accounted for 27% of the food found in the pigs examined. Despite the extensive soil disturbance, researchers found limited or neutral effects on several indicators of forest health.
Although seedlings growing in disturbed patches were shorter, the researchers suggested that pigs might have selected areas where seedlings were already shorter, rather than the digging itself necessarily restricting their growth. Seedling numbers increased at similar rates in disturbed and undisturbed plots over the two-year observation period. Most measures of soil microbial activity also showed no significant differences between the two types of sites.
The researchers concluded that, in the forest they studied, pigs had limited effects on seedling regeneration and soil life. Their influence appeared to be smaller than that of other introduced herbivores, including red deer. Nevertheless, the findings do not establish that wild pigs are harmless to New Zealand’s native ecosystems.
The study did not determine the long-term consequences of their predation on stag beetle populations and other native invertebrates. Earlier research has also raised concerns about their potential impact on native species, including Powelliphanta snails. Several stag beetle species are classified as nationally critical or nationally endangered, making the possible effects of predation an important area for further investigation.
The researchers said additional studies would be needed to assess the wider ecological consequences of feral pigs and determine whether their impact justifies population-control measures. Their findings underline the need to examine effects on individual species and habitats rather than assuming that the presence of an introduced animal produces the same level of damage everywhere.
From an exchange involving two pigs in 1769 to the establishment of widespread feral herds, New Zealand’s experience illustrates how introduced animals can become deeply embedded in a country’s history, economy and environment. The full ecological consequences of their spread, however, remain an area of scientific investigation.
