The dolphin that swam in a warmer Antarctica

By Earth to Sea News · 29 July 2026

A thirty million year old skull has come to Canberra, carrying news from a very different south.

Antarctica has not always been the white silence we picture. Around thirty million years ago its waters were warm enough for dolphins, and one of them was Australodelphis mirus, whose fossilised skull is now sitting in a case in Canberra. It is among the earliest known Antarctic vertebrate fossils from that whole long stretch of time, which makes it rare in the way that a single surviving letter from a lost century is rare. What it offers scientists is a reading of how climate shapes the living world, because an animal is a record of the conditions that made it: what it ate, how it hunted, what the water was doing around it.

The skull is on show at the National Museum of Australia until the eleventh of October, entry free, as part of an exhibition tracing more than a hundred years of Australian work in Antarctica. Meanwhile the present day version of the same detective work is going on at Dome C North, about 1,200 kilometres from Casey station, where an Australian team has just finished a second season drilling for the Million Year Ice Core. Each cylinder they lift holds trapped air, and together they will reach back one to two million years into a period when the rhythm of the planet's ice ages changed. A skull in a glass case and a column of ancient ice, both patiently answering the same question about what the Earth has done before.