The park is a harsh land of ice and rock. Glaciers cover 40% of it. There are 19 peaks over 3,000 m including New Zealand's highest mountain, Aoraki/Mount Cook. The park is also part of Te Waipounamu - South Westland World Heritage Area in recognition of its outstanding natural values.
The glaciers that have helped shape the park's landscape include five major valley systems: Godley, Murchison, Tasman, Hooker and Mueller. The Tasman Glacier, New Zealand's largest and longest glacier, is clearly visible from the main highway at the entrance of the park. Its 27 km long, up to three km wide and 101 sq km. Although covered with rock material in its lower reaches, the ice of the Tasman is about 600 metres deep near the Hochstetter Icefall.
At 3,754 m, New Zealand's tallest peak is known as Aoraki by Māori. According to legend, Aoraki was a young boy in the canoe Te Waka a Aoraki, which was stranded on a reef and tilted to one side. Aoraki and his brothers climbed to the high side and sat on the wreckage. The south wind froze them and turned them into stone, creating the Southern Alps/Kā Tiritiri o te Moana.
In 1851 Captain J. L. Stokes, sailing down the West Coast, gave the mountain its European name, Mount Cook, in honour of the English navigator Captain James Cook.
Plants and animals
There is virtually no forest in the park. Instead the park is alive with the most wonderful alpine plants. Over 300 species of plants are found in the park. Among the most spectacular of these are many varieties of mountain buttercup (Ranunculus) and daisy/tikumu (Celmisia). The famed Mount Cook lily, Ranunculus lyalli, is the largest buttercup in the world.
About 40 species of birds are found in the park, and perhaps the most distinctive of these is the kea, a mountain parrot well known for its mischievous antics. The only true alpine bird is the tiny rock wren/piwauwau, which survives the winter in high rock basins. However kea, falcons/karearea and black-backed gulls/karoro can be found soaring in higher areas.
The braided riverbed of the Tasman is home to the kakī/black stilt, one of New Zealand's rarest birds.
The park is rich with invertebrate fauna, including large dragonflies, grasshoppers, distinctive moths and butterflies. A black alpine wētā known as the Mount Cook flea is found above the snowline. The jewelled gecko lives in the region but is so secretive that it is rarely seen.