Arctic Squirrels Use Steroids to Bulk Up But Don’t Suffer the Consequences
Fat alone couldn’t get these squirrels through hibernation in burrows that get almost as chilly as -10 degrees Fahrenheit
by Marissa Fessenden
Steroid abuse can give men breasts and infertility, while it strikes women with excessive hair and a deepening voice. Anybody injecting too much testosterone and other muscle-building anabolic steroids risks heart enlargement, liver cancer, high blood pressure, heart attacks — and the mania and delusions called ‘roid rage.
Squirrels, however, do fine.
Some squirrels running around with extremely high steroid hormone levels, which help them build muscle before hibernation. But how do they avoid all the negative effects that steroids have on other mammals, like, oh, us? That’s the question that a team of Canada-based scientists have addressed in a new paper, published in Biology Letters.
Arctic ground squirrels, male and female, can ramp up the concentration of androgens in their blood to levels that are 10 to 200 times higher than normal. These androgens—testosterone and other hormones typically higher in males—allow the squirrels to pack on 30 percent more muscle mass before they start their eight-month winter hibernation, the team, led by Rudy Boonstra, reports. These squirrels are carrying an amazing amount of muscle mass—four times that of related Columbian ground squirrels…
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