It might be close, but did you know polar bears are the heaviest amongst the 8 species of bears?
The furry white bears of the Arctic Circle are generally larger than other bears. Coming in at a close second is the brown bear, which is known as the grizzly bear in North America.
How much does a polar bear weigh?
There is a gap between the weight of male polar bears and female polar bears. While male polar bears can weigh between 775-1600 pounds, their female counterparts weigh approximately half of this range. Female polar bears weigh about 330-650 pounds.
Interestingly, at birth, polar bears are actually rather lightweight.
In the rest of this article, we will delve into the details of the polar bear weight and their growth rate.
Table of Contents
How Much Does a Polar Bear Weigh?
The difference in weight and growth rate of males and females is a basis for sexual dimorphism amongst polar bears.
We’ve established that polar bears are the largest bear species. But you will find that the adult males are around 2 times the weight of the females.
On average, a mature adult polar bear will weigh 775-1600 pounds. But the females will weigh around 330-650 pounds.
You may find that polar bears weigh up to 50% more at the end of a successful hunting season. This weight gain is a result of fat accumulated through the period.
While female polar bears are usually lighter than males, they can become quite heavy when pregnant.
In fact, female polar bears have been documented to weigh up to 1100 pounds when pregnant.
Female polar bears gain no less than 440 pounds when pregnant. This weight gain occurs as they build fat reserves necessary when gestating.
Some polar bears have been documented to weigh even more than average. In fact, the heaviest polar bear on record weighed around 2209 pounds.
How Much Do Polar Bears Weigh at Birth?
You’ll be surprised to know that, on average, newborn polar bears are smaller than the average human newborn.
Newborn polar bears typically weigh around 1.5 pounds, with males sometimes weighing a bit more than females.
To put things in perspective, 4-7 newborn polar bears weigh as much as one average human infant, between 5.5-10 pounds.
Newborn polar bears are small, cute, and tiny enough to hold one of them in just one palm of your hand. Considering how big polar bears grow, this might be quite unexpected.
At birth, baby polar bears are not only tiny, but they are also blind, toothless, and helpless.
They also have fur that is so fine it is almost as if the fur is not there. For these reasons, polar bear cubs are totally reliant on their mothers.
For the first few months, polar bear babies remain in the den until the mother believes they can go out.
Within the first month, the polar bear cubs open their eyes. Then within 2-3 months, they step outside the den.
How Fast Do Polar Bears Grow?
Seeing how tiny polar bears are at birth, one might wonder how fast they grow to become huge-sized adults.
In their early days, baby polar bears weigh only slightly over 1 pound.
But they grow very fast, and within 2-3 months, they would have grown 14-20 times their initial size. At this point, they would weigh around 22 to 33 pounds, and this is when they step out of the den.
Outside the den, baby polar bears will keep growing, and after 8 months, they would weigh over 99 pounds.
After a year, they would have grown to almost the same weight as an average man.
Over time, polar bears will keep living with their mothers and feeding on her milk for over 20 months.
The breast milk of polar bears has around 30 percent more fat than that of humans.
This high-fat content contributes to the rapid growth of baby polar bears. Even after a year, the rapid growth will continue as they are breastfed by their mothers.
Are Males Different Weights Than Females?
The weights of male polar bears differ from those of females. Generally, male polar bears are around twice the size of their female counterparts.
This difference in weight is one of the sexually dimorphic traits seen in this species.
Polar Bear Weight Chart
| Age | Pounds | Kilogram | Stone |
| Newborn | 1-1.5 | 0.45-0.7 | 0.07-0.107 |
| 2-3 Months | 22-33 | 10-15 | 1.6-2.4 |
| 8 Months | >99 | >45 | >7 |
| Adult Male | 775-1600 | 350-750 | 55-115 |
| Adult Female | 330-650 | 150-300 | 24-46 |
Resources
- https://www.loc.gov/everyday-mysteries/zoology/item/which-is-the-largest-bear-on-earth/
- https://www.livescience.com/27436-polar-bear-facts.html
- https://www.nationalgeographic.com/animals/mammals/p/polar-bear/
- https://academic.oup.com/jmammal/article/86/5/895/2219068
- https://arctickingdom.com/female-polar-bears-are-truly-the-queens-of-the-arctic/
- https://global.hurtigruten.com/destinations/svalbard/inspiration/wildlife/polar-bear/8-facts-you-didnt-know-about-polar-bears/
- https://www.nwf.org/Educational-Resources/Wildlife-Guide/Mammals/Polar-Bear
- https://seaworld.org/animals/all-about/polar-bear/care-of-young/
- https://www.kidzone.ws/sg/polarbear/polar_bear.htm
- https://www.nathab.com/blog/what-are-the-growth-stages-of-polar-bear-cubs/
