The resillient Ground Squirrel

As A hibernating animal begins its sleep, its bod temperature cools. how low can it go? A dozen arctic ground squirrels appear to have set a record when their body temperature dropped to -2.9 degrees Celsius! At that temperature we would expect their brains to freeze. how does the arctic ground squirrel survive? Every two or three weeks during hibernation, the arctic ground squirrel shiver itself back to its normal body temperature of 36.4 degrees Celsius and does not get cold for some 12-15 hours. Researchers say that this is warming period, although brief, plays a role in the brain's survival. Moreover, during hibernation the arctic ground squirrel's head seems to remain slightly warmer than the rest of its body. During lab experiment, the neck temperatures of the squirrels mentioned above never dropped below 0.7 degrees Celsius.
When squirrel emerges from hibernation, its brain returns to normal activity with two hours. In fact the squirrel's brain works even better after hibernation! Experts are baffled by this astounding recovery. They compare it to new growth emerging from scorched earth within days of forest life.
Researchers hope that their study of arctic ground squirrel will help them understand the human brain's potential more fully. Their goal is to learn more about how to prevent or even reverse the cellular damage that occurs in brain diseases including Alzheimer's

Did the arctic ground squirrel's resilient brain come about by evolution or was it designed? what do you thinks.