Let’s get right to it: baby polar bears go by the name “cubs.” That’s the common word for a baby polar bear, and honestly, knowing that makes it easier to dive into all the fascinating details about their early life in the Arctic.
Picture a tiny, vulnerable animal born in a snowy den, relying completely on its mother for warmth and food.
We’ll look at how cubs grow, how many usually arrive at once, and what makes those first months so unique.
Think about their size, their snowy home, and the changes they go through as they become strong adults.
This article walks you through those stages so you can really imagine the full life of a polar bear cub.
What Are Baby Polar Bears Called?
People call baby polar bears “cubs.” They start out tiny and helpless in a snow den, then grow into yearlings and later subadults as they learn to hunt, swim, and survive.
Difference Between Cubs and Subadults
A newborn polar bear is a cub from birth until about one year old. Cubs arrive blind, toothless, and weigh less than a pound.
Their mother keeps them hidden in a den for months, nursing them with rich milk. By spring, they can weigh 10–15 kg (22–33 lb) and start following their mother outside.
Once they leave the den stage but haven’t reached full maturity, people call them subadults. Usually, that’s around 2.5 to 3 years old.
Subadults still learn a lot from their mother. They practice hunting seals and swimming, but they’re smaller and not nearly as experienced as adults.
Males take longer to mature than females, so “subadult” can mean a pretty wide range of ages and sizes.
How Many Cubs Are Born at Once
Most polar bear litters have one to three cubs, though two is most common. You’ll usually find cubs born in winter inside a maternity den.
The mother fasts and lives off her fat reserves while she nurses her cubs for months. Litter size matters—a smaller litter often means each cub gets more milk and has a better shot at survival.
Females typically breed every two or three years. If food is hard to find, she might even delay pregnancy through something called embryonic diapause, timing births for better survival odds.
In captivity or when times are tough, cub survival drops compared to healthy wild populations.
How Baby Polar Bears Grow Up
Let’s talk about when cubs are born, how mothers protect and feed them, and how cubs pick up the skills they need to make it on sea ice.
Birth and Early Life in Maternity Dens
When a female polar bear gets pregnant, she can actually delay the embryo from implanting. This trick lets her time the birth so she has enough fat to nurse the cubs.
Most births happen in a snow den dug into drifts or a coastal bank. Cubs come into the world tiny—about 500–600 grams—and they’re born blind with only thin fur.
They stay inside the den for about 3 to 4 months, nursing and growing the whole time. The den keeps them warm and out of sight from predators and storms.
When they finally leave, cubs can weigh 10–15 kg, plus they’ve grown thicker fur and stronger limbs.
Mother’s Care and Nursing
Mother bears fast before and during denning, using stored fat to feed and warm their cubs. She nurses them constantly at first, and her milk is loaded with fat so the cubs can build up blubber quickly.
Nursing sometimes lasts 18–30 months, but after the first year, it’s less frequent. The mother also grooms her cubs, touches them a lot, and defends them from danger—wolves, male bears, you name it.
If she doesn’t have enough fat, she might delay pregnancy or, though it’s rare, lose cubs. Groups like Polar Bears International study these behaviors and keep an eye on how changing sea ice makes it harder for mothers to find food and raise healthy cubs.
Learning Survival Skills
You pick up most survival skills by watching and copying your mother for a couple of years. She shows you how to walk on ice, stalk seals at breathing holes, and swim without getting into trouble.
Play-fighting with your siblings helps you build strength and sharpens your hunting instincts. Honestly, swimming doesn’t come easily at first.
You stick to solid ice in the beginning, and only try short swims when you feel ready. Gradually, you put on more blubber and build up the stamina you need for longer journeys.
When you finally leave your mother, you know how to find food along the coast and hunt seals. Still, it takes a few more years before you really feel independent or reach your full size.
