Did I ever tell you about the tale of the bears in Sweden?
Can you tell us?
Previously, bears were shot no matter what, even if they had cubs.
But, as bear populations dwindled, legislators made it illegal to shoot a mother bear with cubs
As a result of this rule, mother bears who stayed with their cubs for longer would not get shot, while mother bears who left their young early were at much higher risk of getting killed.
Over a very short period of time, bears started to stay with their young a lot more
Each individual bear did not learn to stay with her cubs longer, but bears that already had a gene that led to a tendency to stay with her young longer survived and reproduced more often. This meant that there were more of such genes in the gene pool. After a while, this adaptation led to a change in the whole species. Since this change happened so fast, over ten years or so, many critics say that it is not natural selection. But hunting pressures are so high in Sweden that a small change in advantage led to a change in the entire species.