In the Calidocene, Antarctica thaws out due to the amount of C02 released by the holocene extinction event. The continent is mostly tropical grassland along with some forests and wetlands. Its ideal for most life, the problem is, how would anything get there? The solution is simple, swimming, flying or rafting. The frequent storms of the hothouse earth provide animals and other life with large rafts to make it to Antarctica. Animals that traveled by rafting can make it over the ocean by taking 2 routes, drakes passage or by rafting from tasmania, to half of the south island, and finally to Antarctica.
Here are some of the animals whose descendants made the voyage to Antarctica by either rafting, swimming, or flying.
Caimans
Small Galliformes
Small Rodents
Bats
Harbour Porpoises
9 banded armadillo
Possums and Opossums
Gliders
Dunnarts
Monito del monte
Marsupial Mice
Short Beaked Echidna
Barn swallows
Rock pigeon
Some parrots
Some passerine species
Some lizards and snakes
Small amphibians
Epaulette Sharks
Pufferfish
Other small fish
Insects as well as other surviving invertebrates