[2] Like all of New Zealand sub-alpine and alpine grasshoppers S. crassicauda has a 2 or 3 years life cycle.

[3] It can be found as far south as the Right Branch of the Rahu River, Spring Junction (42°17′31″S 172°07′24″E / 42.291844°S 172.123285°E / -42.291844; 172.123285) and as far north as the Thousand Acres Plateau, Matiri Range (41°35′37″S 172°19′21″E / 41.593646°S 172.322454°E / -41.593646; 172.322454).

Alpinacris crassicauda prefer alpine tussock grasslands between 1,200–1,500 metres (3,900–4,900 ft), however, can be found as low as 1,020 metres (3,350 ft) on the Thousand Acres Plateau, Matiri Range (41°35′37″S 172°19′21″E / 41.593646°S 172.322454°E / -41.593646; 172.322454).

Climate change is likely to reduce the suitable habitat that this species can occupy by 10 - 60% of its current range.

Sigaus crassicauda was described in 1967 by Robert Sidney Bigelow,[1] in the genus Alpinacris[5], with type locality of Lead Hills, Boulder Lake (40°53′35″S 172°32′56″E / 40.8931397°S 172.5489702°E / -40.8931397; 172.5489702).