That would be animals getting isolated into different groups in different locations. These animals would have to breed AND adapt to that location, otherwise they will become extinct. When each species adapts and breeds to agree with a different location, that would be called speciation.
A main cause of speciation is when species become geographically isolated.
Explanation:
Speciation refers to a process in which a population turns into a different species. One of the main causes of this is geographic isolation because when a population is separated because of a barrier like a river, this population adjusts to the specific environment and it becomes different from another population that can't breed with the members of this population.
