Its range is exclusively the pack ice around the Antarctica continent. It was first described in the 1840s (on the Ross expedition), and is the smallest and least known of the Antarctic seal species.

It is estimated to have a world population of about 130,000, but a 95% confidence interval means that the population is expected to lie between 20,000 and 227,000 individuals. They are thought to live for 20 years, and be sexually mature at 3 years of age.