Here's why and a breakdown of some examples:
Why Few Shared Animals:
* Continental Drift: Australia and South America were once part of the supercontinent Gondwana, but drifted apart millions of years ago. This isolation led to the evolution of unique species on each continent.
* Climate and Habitat Differences: The two continents have distinct climates and habitats, leading to different evolutionary pressures and adaptations.
Some Overlaps:
* Birds:
* Migratory Birds: Many bird species migrate between the continents, especially seabirds. Examples include:
* Shorebirds: Like the Bar-tailed Godwit, which makes the longest nonstop migratory flight known.
* Seabirds: Albatrosses and petrels are found in both regions.
* Shared Ancestry: Some bird groups share common ancestors, such as the parrots, which are diverse in both regions.
* Insects: Some insect groups, like beetles and butterflies, are widespread across the globe.
* Introduced Species: Humans have introduced various animal species to both continents, creating new overlaps. This includes:
* Domestic Animals: Cattle, sheep, pigs, and horses.
* Feral Animals: Rabbits, cats, and foxes.
Notable Differences:
* Australia: Known for its unique marsupials like kangaroos, koalas, wombats, and echidnas. Also home to diverse venomous snakes and spiders.
* South America: Famous for its diverse primates, including monkeys, as well as jaguars, tapirs, and giant anteaters.
In summary, while there are some overlaps in bird species and introduced animals, Australia and South America are remarkably different in terms of their native fauna.