Summary
10,000,000 years ago, Planet Arda was in an ice age and the global temperature was 13 degrees celsius. Around 9,000,000 years ago the ice caps began to melt and by 8,000,000 years the ice caps were completely gone which ended the tundra biome and resulted in the bottleneck event. The polar bears went to the taiga biome, and in the taiga the temperature is very different. The highest for the winter is 30 degrees Fahrenheit. Usually the bears will hibernate during the winter. During the summer, the highest is 70 degrees Fahrenheit. Polar bears are used to harsh cold temperatures. The subspecies are different because Ursus calvosinis adapted differently than Ursus anorexulis. Ursus anorexulis went extinct because they lost a lot of weight due to the change in diet, they had way too much fur the new climate and they overheated and died. Also, they did not have migration skills or hibernation skills; since the ice caps melted they had to migrate, but they could not and eventually drowned, and the ones that did make it to land were not used to having hibernation patterns and they could not find food. Ursus calvosinis survived because they lost fur, so they were able to comfortably live, they gained weight because they adjusted to the diet and since they had hibernation skills they were able to not die during hibernation because they would not starve. A big adaptation that they had were migration skills. They were able to migrate to the taiga biome instead of staying on ice floes that will eventually melt.