Antarctic land bridge

The Antarctic land bridge was a land bridge connecting the continents of South America, Antarctica, and Australia that existed from the Late Cretaceous to the Late Eocene. The land bridge consisted of the entire continent of Antarctica (at the time unglaciated), as well as much narrower, now-submerged landforms that connected Antarctica to both South America and Australia (with the land bridge between South America and Antarctica sometimes called the Weddellian Isthmus or the Isthmus of Scotia). At its greatest extent, the Antarctic land bridge allowed for a terrestrial connection between South America and Australia, allowing numerous animals and plants to disperse across both continents using it.

The Antarctic land bridge came to an end during the Late Eocene or Early Oligocene, when the formation of both the Drake Passage and Tasmanian Passage cut off any further land connections of either continent with Antarctica. These openings also created the Antarctic Circumpolar Current, which eventually led to the glaciation of Antarctica, making the continent largely inhospitable to any terrestrial life. Signals of the Antarctic land bridge's influence are still present in both the genetics and distribution of many modern animals and plants.