Nanu, a nine-year-old female polar bear, lives on the Hudson Bay lowlands, south of Churchill, Man. Her den, which she dug out of a stream bank before the ground froze, is nearly two metres in diameter and half a metre higher than the narrow exit tunnel. Air heated by Nanu’s body and breath forms a bubble of warmth that rises into the space. While the temperatures outside can be in the –20s in January, the well-insulated cave can be brought to just below freezing with nothing more than her presence.
Though she hasn’t eaten for six months, she’s able to nourish her cubs in utero and still keep her metabolism quiet enough to conserve energy for at least three more months of fasting to come. That’s because, in addition to her own considerable insulation—five centimetres of thick, downy underfur combined with a full mantle of long, hollow guard hairs—every bear has a layer of fat just below the skin.
To save energy, Nanu is able to lower her body temperature slightly from its normal 37°C. In her state of suspended animation in the darkened confines of the den, she delivers two blind, deaf, toothless, downy-haired young who are less than one per cent of her size, with no body fat to speak of.
The cubs, Sivu and Kingu, are immersed in the fur of her belly, where the sound of their mother’s heart is as present and familiar as it was when they were in utero. Mother’s milk, with 32 per cent fat, keeps these tiny, helpless newcomers alive and powers their exponential growth.
By the time they are three weeks old, their fine hair is replaced by a dense undercoat and longer guard hairs. After 25 days, the soles of their little feet start developing hair as well, completing the insulation they need for moving around the den.
Bu hikaye Reader's Digest India dergisinin May 2023 sayısından alınmıştır.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 8,500+ magazines and newspapers.
Already a subscriber ? Giriş Yap
Bu hikaye Reader's Digest India dergisinin May 2023 sayısından alınmıştır.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 8,500+ magazines and newspapers.
Already a subscriber? Giriş Yap
Have Child, Will Travel
Bringing my kid on my around-the-world adventures helped me see her in new and unexpected ways
As Gods Among Us
A photographer explores the gamut of India’s ritual performers who embody deities as a form of worship
My stutter, Myself
If others don't notice my stutter, can I really call myself a stutterer?
Zen and the Art of Motorcycle Modification
A Queensland mechanic customizes bikes so veterans can get riding again
I Tried It...Exercises to Relieve Tech Neck
I STARE AT MY phone for five hours a day.
The Upside of Getting Lost
I was in the woods with my family and we'd lost our way. My phone was dead. It was getting dark. How could this possibly be a good thing?
A MOTHER'S CONVICTION
AFTER ALL FOUR OF KATHLEEN FOLBIGG'S CHILDREN DIED IN INFANCY, A COURT FOUND HER GUILTY OF MURDER. TWENTY YEARS LATER, SCIENCE FINALLY UNCOVERED THE TRUTH
KITT THE COURAGEOUS K-9
Officer Bill Cushing needed a partner. His dog needed a purpose. Together, they rescued each other
Lite, Unplugged
Could you get through seven days without looking at a device? I tried—here’s what happened
GET A GREEN(ER) THUMB
Whether you love digging in the dirt, planting seeds and reaping the bounty that bursts forth, or find the whole idea of gardening intimidating, this spring offers the promise of a fresh start.