[90] The evolutionary pressure of polar bear predation on seals probably accounts for some significant differences between Arctic and Antarctic seals. [69], The polar bear has an extremely well developed sense of smell, being able to detect seals nearly 1.6 km (1 mi) away and buried under 1 m (3 ft) of snow. The cub’s mimicking habits probably makes easy for their mother to teach them hunting techniques. Polar bears have been observed to hunt the small Svalbard reindeer (R. t. platyrhynchus), which weigh only 40 to 60 kg (90 to 130 lb) as adults, as well as the barren-ground caribou (R. t. groenlandicus), which is about twice as heavy as the former. This is quite unique in many other terrestrial mammals. Polar bears appear to be less affected by infectious diseases and parasites than most terrestrial mammals. That is to say nearly half of females living in the Hudson Bay are reproductive each year. [71] One bear swam continuously for 9 days in the frigid Bering Sea for 700 km (400 mi) to reach ice far from land. [193], Many chemicals, such as PCBs and DDT, have been internationally banned due to the recognition of their harm on the environment.

[203][204][205][206] Second, controls of harvesting were introduced that allowed this previously overhunted species to recover. The mother bear is likely to go through strategic weaning in which there is a limited suckling.

[43], In August 2011, Environment Canada published a national polar bear conservation strategy. Canada allocates a certain number of permits each year to sport and subsistence hunting, and those that are not used for sport hunting are re-allocated to indigenous subsistence hunting. The family remains in the den until mid-February to mid-April, with the mother maintaining her fast while nursing her cubs on a fat-rich milk. [180], The International Union for Conservation of Nature, Arctic Climate Impact Assessment, United States Geological Survey and many leading polar bear biologists have expressed grave concerns about the impact of climate change, including the belief that the current warming trend imperils the survival of the polar bear. Ursus eogroenlandicus [188], In Alaska, the effects of sea ice shrinkage have contributed to higher mortality rates in polar bear cubs, and have led to changes in the denning locations of pregnant females. The most popular color? Believe it or not, baby polar bears can climb trees. ", "WWF — Polar bear status, distribution & population", "Bear hunting caught in global warming debate", "Ask the experts: Are polar bear populations increasing? [136] Adult polar bears are occasionally vulnerable to predation by orcas (Orcinus orca) while swimming, but they are rarely reported as taken and bears are likely to avoid entering the water if possible if they detect an orca pod in the area. Their concentrations in polar bear tissues continued to rise for decades after being banned, as these chemicals spread through the food chain. Cubs are walking on the fallen tree. Females communicate with their young with moans and chuffs, and the distress calls of both cubs and subadults consists of bleats. [145] Almost all parts of captured animals had a use. Photos taken by Arctic expedition leader Jens Wikström show the pair of two-year-old siblings having a game of tug-of-war with a black plastic bag, highlighting the ongoing problem of plastic pollution. In Canada, Svalbard, and Alaska, the mean litter sizes are 1.9, 1.81, and 1.61 respectively. Ursus jenaensis

According to population surveys from 2017 there was thought to only be 250 bears that roam the costal region around Svalbard. Norway is the only country of the five in which all harvest of polar bears is banned. [43] The Polar Bear Specialist Group of the IUCN Species Survival Commission takes the position that "estimates of subpopulation size or sustainable harvest levels should not be made solely on the basis of traditional ecological knowledge without supporting scientific studies. They play with anything they can possibly get their hands on. Polar bears are popular in fiction, particularly in books for children or teenagers.