Polar Bear Facts

Tag: Female Polar Bear

  • How often Do Polar Bears have Cubs? – Polar Bear Giving Birth

    In this article we are going to discuss about polar bear giving birth to its cubs as well as the bear’s birth interval.

    How often Do Polar Bears have Cubs?

    Studies indicate that most females wean their cubs after two and a half years, which suggests that they can afford to mate once every three years. According to scientists, the female bears inhabiting Beaufort Sea are thought to mature earlier than those living in other areas. The weaning time and the birth interval of Beaufort Sea population is the same.

    In 1990s

    In rare instances, scientists have also observed female polar bears keeping their babies for as long as three and a half years. In the 1990s, a few individuals reported to wean after three and a half years in the Viscount Melville Sound. Even so, another female reported to have her cubs around her for up to four and a half years. According to Ian Stirling the likely reason could be that bears were probably living in less productive habitats where multiyear sea ice didn’t occur as much. Plus, the ringed seals weren’t abundant in the Viscount Melville Sound. As it turns out, a less accessible food might have probably slowed the growth rate of polar bear cubs, resulting in a delay in the age at weaning.

    Another explanation for the delay in weaning (in 1990s) could be due to overharvesting in adult males. The adult males could have been less frequent which would drive away the cubs from their mother. However, Viscount Melville Sound isn’t protected by multiyear sea ice anymore perhaps due to climate change therefore; polar bears can afford to hunt ringed seals.

    In 1980s

    If we go back to the 1980s we observe 40% of all polar bear females could successfully wean their cubs at only one and a half years of age in the western coast of Hudson Bay. As it turned out, nearly all females would breed every two years which may have allowed them to produce 30% more litters in their entire lives.

    Nonetheless, when scientists compared the mortality rate in yearlings that were weaned right on time against those which took additional time, they found interestingly no major difference. Both had lived more than their average lifespans. They also observed that the survival rate of one-year-old cubs in the Hudson Bay was probably the same as that of two-year-old cubs inhabiting rest of the Arctic.

    Why the Hudson Bay Females are more Productive than others

    1. Studies indicate that some of the females in the western coast of Hudson Bay have successfully raised their cubs so that the yearlings hunt on their own. The reason behind is that the snowdrifts in the Hudson Bay melts relatively earlier, and as it softens, the yearlings which are probably not too heavy to break the ice, can hunt ringed seals at their breathing holes.
    2. Another reason as to why Hudson Bay females produce more frequently than others is that the Hudson Bay itself is biologically productive. The rivers that end up with the Hudson are thought to bring many nutrients which indeed attracts large seal population. Since they are the primary food of arctic bears, the bears of all ages might have less difficulty catching food.
    3. Studies have also shown that the Hudson Bay is home to a large number of bearded seals. The bearded seal is nearly five times the size of a ringed seal. The larger food source means larger carrion remaining on the sea ice. Yearlings often find it hard to hunt and so they mostly rely on left-over carrion. They are going to eat seals by scavenging the kills until they are big enough to hunt on their own

  • When Do Polar Bear Cubs Leave their Mother?

    In this article we’ll be studying how long do polar bear cubs stay with their mom and when do they leave her. Female polar bear is an extremely dedicated mother in that she prefers to have cubs around her for as long as 2 to 3 years after birth. That’s a pretty long period isn’t it? During the long nursing period, the mother teaches her cubs just about everything including hunting and swimming. Let’s see when do baby polar bears leave their mother.

    When Do Polar Bear Cubs Leave their Mother?

    The typical weaning period of polar bear cubs is about 2.5 years but it also varies. Sometimes the cubs leave their mother around 2 years while at others they wean later than 2.5 years. But normally cubs will stay with their mother for no more than 2.5 years.

    Sometimes it so happens that a female polar bear doesn’t find her mating partner when the time is due. In that case, the cub likely stays with its mother until the mother actually abandons it herself. Researchers have yet to understand fully the phenomenon of weaning yearlings in polar bears. It’s pretty challenging for a mother to wean her present cubs for she must prepare herself for another litter by storing enough fats.

    How Does the Mother Decide to Leave her Cubs?

    It depends on numerous factors such as;

    • The size of offspring;
    • Availability of food;
    • Maternal condition, and
    • Willingness of a mating partner.

    The mother bear assesses all the above factors to decide for the ideal weaning time. When the mother is in estrous, the adult male likely chases the young and attempts to drive it away from her mother. The young polar bear soon learns that it’s time to live an independent life on its own as it is no longer wanted.

    Read More: How Do Polar Bears Reproduce?

    A mother walks alongside her cubs. When do polar bear cubs stay with their mother? Photo by Natural World Safaris
    • While it may seem odd in the first place the family break-up is quite natural in polar bears. Cubs play, fight, and eat under the watchful eye of their mother until they come of age by which they’ll gain independence.
    • When they attain 2 years of age, they’ll walk away. Now they can hunt on their own and they owe much to the efforts of their mother. Perhaps this is a significant part of the weaning process.
    • The strong bond between the mother and her cubs weakens as the latter grow older. If a mother intends to leave her young she just walks away from her offspring straightaway.
    • Young bear can follow the mother and track down her but soon they realize that they must start hunting instead of searching for their mother. However, sometimes the young just doesn’t listen to their mother’s warning and they prefer to stay.
    • As it turns out, the mother briskly chases the young to tell him that it must walk away. Mother and young often travels for months before they fall apart.

    Back in 80s, the polar bear population in the Hudson Bay used to leave their mother as early as 1.5 years. Studies claimed that around 55% of all cubs became independent of their mother before reaching 2 years age. That is however an exception rather than the rule. Scientists have not been to understand as to why polar bear cubs leave their mother so early.

    1. The early weaning might be due to the condition of their mothers as well as the sex of young bears.
    2. There can be another possibility which is that seals could be widespread in the early 80s—helping the young bears to grow quickly.
    3. On the Hudson Bay three different polar bear populations may have mixed. Adult males might have possibly taken the females away from their young too early.
    4. Or females may have faced food scarcity in autumn and they stopped nursing before coming to estrous again in the following year.
    5. Females may choose to have more litters in their lifetime and so they abandon their current offspring.

    Grizzly mothers usually nurse their cubs for one extra year if they feel like their yearlings are not old enough to live on their own. They do so in order to increase the likelihood of their survival. Polar bear mothers do not treat their cubs like grizzlies yet they (yearlings) manage to survive just fine. While they cannot become expert hunters they do nevertheless become scavengers to make a living. Currently, weaning before 2 years of age is probably not common. Furthermore, the sea ice in the Hudson Bay is disappearing relatively earlier forcing polar bear mothers to wean their cubs for until they reach 2.5 years of age.

    How Long Do Polar Bear Cubs Stay with their Mother? – Video

  • How Heavy is a Polar Bear?

    Polar bear is a pretty heavy animal—probably the heaviest of all carnivorous land mammals. Siberian tiger is just about the same weight as polar bear but the latter is slightly heavier. Therefore, polar bears do not have any natural predators in the Arctic. However, when they born they are only as heavy as an adult ground squirrel. Now let us see how heavy is a polar bear in the wild?

    How Heavy is a Polar Bear?

    Mature male bears average 350–700 kg (772–1,543 lb) in weight but most bears weigh 800 – 900 pounds. Adult males are two times heavier than adult females. However during dormancy the female polar bears put on too much weight—reaching the weight of adult males.

    A Polar bear spreads its body weight to prevent herself from falling into the water.
    Photo by DailyMail.

    In the Beaufort Sea, the adult males are reportedly as heavy as 450 kg (992 lb) whereas mature females average 150–250 kg (331–551 lb) in weight. During pregnancy, the female reaches the weight of 1,100 pounds. Many a times it happens that a polar bear spreads its legs while walking on the thin ice. It does so in order to distribute its body weight equally so the bear doesn’t fall into the water. When the Arctic ice is not thick enough to support the bear’s weight, the polar bear cannot hunt for seals because it uses dense ice as a hunting platform. Consequently, the polar bear spends weeks sometimes even months in starvation.

    According to the Guinness Book of World Records, the maximum polar bear weight is recorded at 385 to 410 kg (849 to 904 lb) but conservationists have found polar bears weighing more than 1,000 pounds in the wild. There’s no mass comparison of polar bears with any other ground-dwelling Arctic species—the white bear is clearly the biggest and the heaviest of all Arctic mammals.

    How Heavy is a Polar Bear? – Video showing a polar bear walking on a thin ice.

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  • How Much Does a Polar Bear Weigh? – Polar Bear Weight

    Polar bear weight varies with the season because of the availability of food sources. The adult males are generally heavier than adult females. Ursus maritimus are sexually dimorphic in fact one of the most dimorphic mammals in the marine world. Polar bear cubs weigh less than a kilogram but male cubs are greater than female cubs even at birth. Now let us study how much do polar bears weigh?

    How Much Does a Polar Bear Weigh? – Polar Bear Weight

    A full grown polar bear weighs as much as 350–700 kg (772–1,543 lb) but the average weight measure around 385 to 410 kg (849 to 904 lb). Males attain this much weight when they are 10 years of age. Kodiak bears are slightly heavier than adult white bears.

    In the Beaufort Sea, males average 450 kg (992 lb) on maturity. They are nearly twice the weight of females. The heaviest male polar bear ever recorded was 1,002 kg (2,209 lb). The bear was shot in northern Alaska (Kotzebue Sound) in 1960.

    Read More: How Big is a Male Polar Bear?

    A mother bear is followed by her cubs. How much do polar bears weigh? Photo by: GUDKOV ANDREY/Shutterstock

    How Much Does a Female Polar Bear Weigh?

    The weight of an adult female is one half of the male’s body mass. Females weigh around 150– 250 kg (331–551 lb).The maximum reported weight in females is 260 kg (573 lb) but it is extremely rare. During pregnancy adult females put on too much weight almost equal to adult males’ mass. Females gain as much as 500 kg (1,102 lb) weight when they are pregnant.

    During pregnancy adult females put on too much weight almost equal to adult males’ mass. Females gain as much as 500 kg (1,102 lb) weight when they are pregnant.

    Females attain sexual maturity at 6 years of age. Soon after age they will put on much weight because of pregnancy. Extra weight is not because of cubs but due to the extra fats which she stored. She must store excess fats in order to spend days in the without eating. The female will come out of den in the spring season.

    How Much Does a Polar Bear Cub Weigh?

    Main Article: How Much Does a Baby Polar Bear Weigh?

    The polar bear cubs weigh 1 – 1.5 pounds (0.8 kilograms) at birth. Females are smaller and less heavy than males at birth. When the cubs reach 90 – 100 days age they leave the den. At this time they weigh up to 33 pounds (115 kg). A cub born in the Alaskan zoo averages 18 pounds (8 kg) and the bear was 90 days old.

    How Many Pounds Does a Polar Bear Weigh?

    Polar bears weigh around 772 to 1,543 pounds but most bears weigh less than 1,000 pounds. The heaviest polar bear ever recorded at the Guinness Book of World Records measured at 849 to 904 pounds. The average weight of a female polar bear in pounds is about 573 pounds.

    How Much Does a Polar Bear Weigh? – Video

  • Female Polar Bear | Size, Weight, Denning Behavior, Affection

    A female polar bear is less than half the size of a male polar bear. She is also much less in weight as compared to their mating partners. A female bear attains maturity in just 4 – 5 years but if the food is abundant she becomes mature in 3 years. Every spring she enters into hibernation sort of state (dormancy) and remains inactive in her den. This is a period of pregnancy and she leaves the den only after the cubs are able to run along with her. The female polar bear is thought to be highly devoted and dedicated mother as she continues to nurse her cubs for as long as 1 – 2 years.

    What is a Female Polar Bear Called?

    A female polar bear is called sow. Sow remains inactive for almost half of the year. She spends these inactive hours in her den.

    How much does a Female Polar Bear Weigh? | Female Polar Bear Weight

    Adult females weigh no more than 150 – 250 kg (331–551 lb) with the overall length measuring up to 1.8–2.4 meters (5 ft 11 in–7 ft 10 in). The maximum weight ever recorded in adult females is about 260 kg (573 lb). During pregnancy when they are about to enter den they weigh as much as 500 kg (1,102 lb).

    Soon after mating the sows will eat large amount of food in order to store fat reserves. These fat reserves are pretty useful during dormancy. During these days sows put so much weight that they become compatible with adult males.

    Denning Behavior

    A sow is adaptable to survive many weeks in starvation especially during late summer and early fall. During warmer months when the ice floes break up sows begin to dig maternity dens in which they are going to spend the next four months in hibernation. The den consists of 3 to 4 chambers with a narrow opening. They preferably make dens in drift snows but if the snow is not thick enough the dens may be shifted underground. The underground dens are usually made 2 – 3 kilometers from the coast.

    A Female polar bear nursing her cubs. Chelsea Tischler — National Geographic Your Shot

    Hunting Seals

    She prefers to hunt young bearded or ringed seals because the adult seals are too large to be handled by sow alone. Only mature boars are strong enough to take down adult seals.

    How Do Female Polar Bears Communicate with their Young?

    When adult females want to communicate to their young they produce a couple of sounds such as chuffs and moans. However the distress or a mayday call consists of bleats. She utters huffs or snorts or growls when she feels threatened or nervous.

    Female bears will communicate with adult males by leaving their scents behind so that males follow the track. The verbal communication and chemical composition go side by side in bears.

    Affection with her Cubs

    Sows are one of the most affectionate mothers in the carnivorous mammals. They never leave the cubs unattended. Many a times it happens that a female polar bear adopts a wild cub and a cub becomes the permanent member of her family unit. She actively guards her cubs against any potential predator including mature bears. The boars are known to kill cubs and sometimes eat them when they are hungry.

    Female Polar Bear Lifespan

    The maximum lifespan of a female polar bear is 43 years which is of a captive specimen that died in 1991.

    Female Polar Bear – Video

  • Difference Between Male and Female Polar Bears

    Male and female polar bears not only differ in their sizes but also somewhat in behavioral traits. Polar bears are the most sexually dimorphic mammals that is to say there is a significant and obvious difference in their sizes as well as in weight.

    Male polar bears are nearly twice the size of female bears. The typical weight of an adult male is about 450 kg (992 lb) in contrast to female’s weight of 150 – 250 kg (331–551 lb). Clearly there is a substantial difference in weights. Similarly the female is also smaller in body length as compared to males.

    Difference Between Male and Female Polar Bears

    Mature males are far more aggressive than adult females. Cannibalism is quite common in male bears as they often engage in killing and sometimes eating cubs that belong to the other social unit.

    Females are extremely devoted mothers whereas males take no part in raising cubs. The female bears take the responsibility not only for rearing cubs but also to protect them against predators. Many a times it is seen that a female in a desperate attempt to relocate to a new dens, carrying cubs in her mouth. The devotion of a female bear is so much so that she can even rear a cub that doesn’t originally belong to her family.

    Males neither defend their social unit nor do possess any unusual skills as a father. They just remain with female for as long as two weeks after which they leave once for all.

    Difference Between Male and Female Polar Bears – Video