Individuals can survive the cold by freezing solid at any life stage, at any time of the year.

Sigaus australis can be found in the southern half of the South Island, from Otago and Canterbury regions.

Evidence from mtDNA sequencing suggests that S. australis encompasses several narrow endemic taxa and one widespread species.

[7]Sigaus australis would have been more widespread during the last glacial period with both morphological and genetic signature of greater population connectivity in the past.

[6] With climate warming and low dispersal potential, S. australis will probably lose 75% to 93% of its suitable habitat by 2070.