What would happen if a new predator was introduced into the ecosystem that only ate mice?

The ecosystem would drastically change.

Explanation:

Here is a food chain that involves mice:

Sunlight - > Berries - > Mice - > Snake - > Bald Eagles

So, let's say a new animal was introduced, and it eats mice. There would be more berries, as the mice wasnt eating them, the snakes would start to starve as there is not as many mice, and the bald eagles may start to starve as no more snakes for them to eat!

I hope you understand, and have a wonderful day!

He may not know to use ecosystem in overcoming his hunger, he may end up. starving and at last he would choose to eat plants and he will adapt with the nature of ecosystem.

In second case,

he may get disturbed / fruatated and destroy the whole ecosystem.

in third case,

he may not know how to use the ecosytem and die not eating anything.

So, if overall we see, our animal may die in two cases. the only case how an meat eating animal will survive in new environment is by adapting himself, but is he could not then he will die. so living - dying ratio is 1:2. so we can predict that the animal will not survive. But as we know animals are not like new era humans and dont have tantrums like em', so they will adapt. but adaptations take a lot time, before that the animal dies because of aging then nothing can be done.

Infact, this is how humans has evolved from a monkey to a social animal. we all know that humans have been fast devaloping animal and thats what we are today, but there was no one to force human to evolve as a whole im trying say there was no disturbance because of any other species in case of human.

so because of disturbance that animal may or may not adapt.

the answer is depends.