Estimations of growth and age have only been attempted for a quarter of the species known. This species has a medium-sized body with a tapered whip-like tail. Its length is up to 1.12 m. It can be distinguished from H. novaezealandiae and H. homonycteris as it has a pale silvery colour with no patternation or spots. Estimates suggest that they can live between 15 and 22 years, although the lack of data still makes this unreliable.