A giant native spider confined to two remote islands for more than a century could one day return to parts of the Chatham Islands, as conservationists work to restore the habitat it needs to survive.
The Rangatira spider was one of New Zealand’s largest spiders, with females weighing up to five grams before laying eggs — almost as much as the country’s smallest bird, the tītitipounamu, which weighed about six grams.
Despite their imposing size, Rangatira spiders were relatively friendly and spent most of their days hidden in logs and tree holes before emerging after dark to hunt wētā. At night, their shiny eyes can be seen from 20m away.
Habitat loss and the presence of predators were believed to have wiped the species out across much of the Chatham Islands archipelago, where it previously inhabited multiple islands.
It was now confined to two small nature reserves offshore of the Chathams, on Hokorereoro/Rangatira and Maung’Re/Mangere islands.
The spider had not been recorded on the main Chatham Island, Rēkohu Wharekauri, or Pitt Island for more than a century.
While the species remained relatively abundant on its two remaining island homes and was not considered at imminent risk of extinction, it was classified as "At Risk: Relict" by the Department of Conservation.
Its restricted range now meant the population remained dependent on a small area of protected habitat, leaving it vulnerable to environmental changes or new threats reaching the islands.
The Chatham Islands Landscape Restoration Trust was now carrying out predator eradication work aimed at restoring native ecosystems across the archipelago, which could eventually help the spider return to parts of its former range.
"To bring them back, they need the right conditions: a forest with large, old trees, a healthy wētā population to feed on, and protection from predators such as mice, rats, possums, and weka," Predator Free NZ said in a Facebook post.
Restoring suitable habitat elsewhere in the Chathams would reduce the species' reliance on its two remaining island refuges, and would provide safe alternative places for future generations of Rangatira spiders.
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