How come there are no wild emu in north America ?

Question

I know they are not native BUT they do well in any climate and do well foraging for food and water . They wouldn't be any easier pray than deer. So pigs get out and go wild , why has this not happened with emu .

Answer 1

Big flightless birds never adapted to the cold weather unless they were exceptional swimmers [penguins].

S. America and Africa have large flightless birds [emu, ostrich] and before Australia [elephant bird].But Eurasia and N. America only had large flightless birds periodically.



Not saying they are incapable of adapting to these environments but before the massive continental collisions around 30 million years ago, megafauna near the equator had big flightless birds and mammals [both herbivorous and carnivorous]. North of that megafauna was almost exclusively mammalian with the only birds being flyers or swimmers.



When the continents collided you had a massive life exchange and most big birds went extinct [likely due to their size constraint [due to their stance, that is another topic]]. A size constraint led to their incapability of competing with large mammalian carnivores/herbivores unless they could run away or fly away.

A few big birds made it northward and had success but it was short lived [3 million years] because the iceage wiped those out [as it did many mammals]. Not saying big birds like the ostrich can't adapt The only big flightless birds that survived continental collision were fast runners. Australian elephant birds survived because they NEVER collided with another continent [they recently went extinct when humans arrived], New Zealand and islands have several flightless birds which survive today because they are also isolated.



Birds are the most successful vertebrates on land today [by far most species], they are the only relatives of the most successful vertebrates to ever walk the earth [the dinosaurs] but they originally evolved for flight and are incapable of competing with largest placental mammalian carnivores or herbivores unless they can fly/run/swim away.

Answer 2

Ratites, like the ostrich, emu, cassowary, kiwis, rheas, and tinamou have evolved in the landmasses of Africa, Australia, South America, all of which were part of Gondwana. North America and Eurasia were in a different landmass, called Laurasia.

Answer 3

The rattites (emu, rhea, ostrich, cassowary, etc.) evolved in the southern hemisphere and only are in the land masses that broke apart at those longitudes as the continents separated.

Answer 4

You have answered your own question. Emus, indeed all ratites, are not indigenous to North America. Presumably those who hold emus in captivity in North America ensure there are no escapes.

Answer 5

Emu and other ratites (large flightless paleognath or ancient palate birds) evolved from flying ancestors after the extinction of the dinosaurs in the Southern Hemisphere. They therefore have no way of reaching North America, since they could not fly. At that time, Africa and South America were very far away from North America, and they were also separated by oceans. The Bering Strait connected Asia with North America at times, but the ratites were not able to reach NE Asia, and so they were not able to cross the Bering Strait to reach North America.



The emu is not native to South America, so even though South America eventually collided with North America several million years ago, the emu was not able to reach North America either. Beside, by that time, big cats like lions and tigers already evolved. The ostrich was able to evolve fast running so it could coexist with lions. In South America, the rheas are also fast runners, but in order to reach North America, they would need to cross the dense woodlands and forests of Central America and Mexico. Since they are not adapted to forests, where they would have difficulty relying on speed to escape predators, they were not able to migrate to North America.

Answer 6

Because people brought them here . I own an emu for instance. That's why I'm asking . Why haven't some gone wild ? They seem like an animal that would do fine

Answer 7

They didn't develop in America independently, and they don't fly or swim. So how would they get here?