After the last major ice age, sea levels around the world rose. As they did, the rising waters divided what was once a single island in the North Sea into two different islands. A population of rabbits was split between the two islands. Ten thousand years passed with no contact between the two rabbit groups. In recent times, a scientist attempted to breed individuals from the two groups, but he was unsuccessful in doing so. Why were rabbits from the two groups unable to produce offspring together?
