Do you have any idea how many babies do polar bears have at a time? In this article, we’ll try to explain just about anything on the reproductive biology of polar bears. The polar bear litter size generally depends on quite many things which is why each polar bear population has its own litter size. Twins are common throughout much of the polar bear range. Triplets are extremely rare.
How Many Babies Can a Polar Bear have?
Ian Stirling, a leading polar bear scientist, suggests that more than two-thirds of the litters consist of twins. It’s fairly common for a female polar bear to produce two cubs at time. While twins are almost the norm, about 20% to 30% of the polar bear’s reproduction produces a single cub.
Scientists have rarely observed triplets because the litter size generally depends not only on the time frame—it also rests on the geographic distribution. In 1908s, Ian Stirling had examined 119 litter sizes in the Western Hudson Bay out of which 20% mainly consisted of twins; only 12% were triplets, and he witnessed a single case of four cubs.
When scientists examined the litter sizes in the Canadian High Arctic, Svalbard, Beaufort Sea, and the Baffin Island, they observed that only 1 to 3% of all litters were triplets.
However, when scientists examined the litter sizes in the Canadian High Arctic, Svalbard, Beaufort Sea, and the Baffin Island, they observed that only 1 to 3% of all litters were triplets. The litter sizes in these areas were four times lesser than the one observed in the Hudson Bay.
Over the past 15 years, the triplets have become less frequent as they were in 1980s. They are still recorded nevertheless.
Read More: Polar Bear Cub
What are the Factors that Determine the Polar Bear Litter Size?
It’s a pretty tough ask to measure the polar bear litter sizes because scientists mostly count when polar bear cubs emerge from the dens. They just can’t find out how many cubs are unable to make it outside the den before they are weaned. Scientists do however aware that the litter size might be greater than they initially anticipated since a few cubs likely die of natural causes inside the den.
Read More: How Do Polar Bears Reproduce?
The average number of polar bear babies in the spring season ranges from 1.5 to 1.9 depending on the location. Andrew Derocher, a leading polar bear researcher, claims that there seems to be no real relation between the litter sizes and latitude. It is quite possible that different litter sizes are observed in different time periods. Therefore, it is logical to assume that the litter sizes primarily depend on the availability of food as well as other environmental conditions instead of latitude. As a rule of thumb, the litter size decreases as more cubs die naturally. Still, scientists find it pretty hard to measure the original litter size when they see a female polar bear with her cub. That single cub doesn’t tell anything about its siblings which might have possibly died before weaning.
In the winter of 1937, Father Van de Valde had obtained data on the polar bear litter sizes from various sites he traveled along the way. He observed the average litter size of 1.88 to 2.0 cubs from December to February.
In 1970s, the largest litter sizes were recorded long the southwestern coastlines of Hudson Bay. Dick Robertson and Dale Cross had observed the litter sizes from the air. The average litter size was found to be 2.0 which were probably the greatest. Paul Prevet and George Kolenosky also tracked polar bears along the northern Ontario coast somewhere between 1974 and 1978. They also found the litter size to be 2.0.
The birth doesn’t appear to occur in the same month throughout the arctic. In the Hudson Bay cubs are born in mid-November to mid-December. In some regions the birth occurs in the last days of November. In the Beaufort Sea female bears mostly enter into the den in the early December. In captivity the birth may occur as late as in December 27. The female body condition determines the timing of implantation.