The islands are mainly coral and sand, though some have grassy or low shrub vegetation. They are the home of 49 seabird species and also turtles that nest in the sand. Abundant marine life inhabits the clear waters, and the island has stopover facilities for visitors to the Great Barrier Reef Marine Park. There is no population apart from a manned weather station on Willis Island. Australia claimed the territory in 1969.
Glaciers cover much of it.
The islands have no permanent human population. Plant cover is sparse, but Heard and McDonald support many seabird breeding colonies, including penguins and albatross. Elephant seals and leopard seals frequent the shores. During the 19th century, the seals and penguins were exploited for oil. Australia gained control of the islands from Great Britain in 1947.