Within it's arctic realm, polar bears exist at the top of the food chain (Richardson & Vongraven, 2011). As such, the population of these carnivorous bears is heavily dependant on those species within the food chain.
PREDATOR VS. PREY Relationship
Bearded seals are a polar bear’s main food source (Unger, Z., 2014). Polar bears mainly hunt these seals by waiting for them to emerge from their self-made "breathing holes," as seen in Figure 1b (Unknown 3). Polar bears also hunt bearded seals by swimming in the water close to land or ice, scouting out their prey (Richardson & Vongraven, 2011). They stay in a close proximity to the land or ice in order to drag their prey out of the water and conveniently eat (Richardson & Vongraven, 2011). The bearded seals' blubber provides the polar bears with lots of energy that they will need to survive. Especially as global warming progresses, polar bears have a greater demand for energy to travel long distances to either find food or a suitable habitat (Government of Canada, 2014). The bearded seal's blubber also provides polar bears with insulation to keep them warm in the freezing Arctic weather. An increase on the population of seals yields an increase in the population of polar bears-- assuming climate change is controlled to have no effect on the status of polar bear populations (World Wildlife Fund, 2008). A decline in the seal populations yields a direct decline in the polar bear population(World Wildlife Fund, 2008). Seals also depend on the thick sheets of ice as breeding land, and with the melting of this ice, their population declines as well (World Wildlife Fund, 2013).
PREDATOR VS. PREY Relationship
Bearded seals are a polar bear’s main food source (Unger, Z., 2014). Polar bears mainly hunt these seals by waiting for them to emerge from their self-made "breathing holes," as seen in Figure 1b (Unknown 3). Polar bears also hunt bearded seals by swimming in the water close to land or ice, scouting out their prey (Richardson & Vongraven, 2011). They stay in a close proximity to the land or ice in order to drag their prey out of the water and conveniently eat (Richardson & Vongraven, 2011). The bearded seals' blubber provides the polar bears with lots of energy that they will need to survive. Especially as global warming progresses, polar bears have a greater demand for energy to travel long distances to either find food or a suitable habitat (Government of Canada, 2014). The bearded seal's blubber also provides polar bears with insulation to keep them warm in the freezing Arctic weather. An increase on the population of seals yields an increase in the population of polar bears-- assuming climate change is controlled to have no effect on the status of polar bear populations (World Wildlife Fund, 2008). A decline in the seal populations yields a direct decline in the polar bear population(World Wildlife Fund, 2008). Seals also depend on the thick sheets of ice as breeding land, and with the melting of this ice, their population declines as well (World Wildlife Fund, 2013).
COMPETITIVE Relationship
The Arctic fox is one of the only species other than the bearded seal that interacts with the polar bear. The Arctic fox and the polar bear both occupy the same habitats and compete for food supplies to survive (Unger, Z., 2014). When the Arctic fox hunts and eats its prey, it stores the rest of its food in dug out spaces known as “snow holes” (World Wildlife Fund, 2008). Polar bears have a strong sense of smell, and can detect food even if it’s buried under a thick blanket of snow (Unger, Z., 2014). Especially as the weather becomes warmer with the ice melting, it takes lots of energy out of the polar bears to hunt for their food in the Arctic Ocean. In order to satisfy their hungers, the polar bears dig up and steal the food stored by other carnivores of the Arctic, like the Arctic fox (Woodward, J., 2008). Arctic foxes also steal from polar bears. When polar bears first hunt their prey (bearded seals) they only eat the skin and blubber for immediate energy and warmth (Unger, Z., 2014). Like the Arctic foxes, polar bears also store the remainder of their food in dug up snow holes, since it may be a long time before they are able to hunt again (Woodward, J., 2008). Arctic foxes also have a strong sense of smell, however unlike polar bears, they are unable to hunt large prey like the bearded seals-- they do not have the anatomy to swim in water like polar bears do (World Wildlife Fund, 2008). Instead the Arctic fox uses its fast digging skills to steal the carcass from the polar bear's snow hole (Unger, Z., 2014). In total, one species will steal a part or all of the other species’ food supply when their own food supply runs out, making this a competitive relationship between the polar bear and the Arctic fox. If the Arctic fox population were to increase, the polar bear populations would decline as a result of less food supplies being available due to competition (Unger, Z., 2014). Less food supplies leads to a lower survival rate for the polar bear populations. On the contrary, if the Arctic fox population were to decline, the polar population would increase as a result of less competitive activity for food supplies (Unger, Z., 2014). More food supplies would lead to a higher survival rate for the polar bear populations.
The Arctic fox is one of the only species other than the bearded seal that interacts with the polar bear. The Arctic fox and the polar bear both occupy the same habitats and compete for food supplies to survive (Unger, Z., 2014). When the Arctic fox hunts and eats its prey, it stores the rest of its food in dug out spaces known as “snow holes” (World Wildlife Fund, 2008). Polar bears have a strong sense of smell, and can detect food even if it’s buried under a thick blanket of snow (Unger, Z., 2014). Especially as the weather becomes warmer with the ice melting, it takes lots of energy out of the polar bears to hunt for their food in the Arctic Ocean. In order to satisfy their hungers, the polar bears dig up and steal the food stored by other carnivores of the Arctic, like the Arctic fox (Woodward, J., 2008). Arctic foxes also steal from polar bears. When polar bears first hunt their prey (bearded seals) they only eat the skin and blubber for immediate energy and warmth (Unger, Z., 2014). Like the Arctic foxes, polar bears also store the remainder of their food in dug up snow holes, since it may be a long time before they are able to hunt again (Woodward, J., 2008). Arctic foxes also have a strong sense of smell, however unlike polar bears, they are unable to hunt large prey like the bearded seals-- they do not have the anatomy to swim in water like polar bears do (World Wildlife Fund, 2008). Instead the Arctic fox uses its fast digging skills to steal the carcass from the polar bear's snow hole (Unger, Z., 2014). In total, one species will steal a part or all of the other species’ food supply when their own food supply runs out, making this a competitive relationship between the polar bear and the Arctic fox. If the Arctic fox population were to increase, the polar bear populations would decline as a result of less food supplies being available due to competition (Unger, Z., 2014). Less food supplies leads to a lower survival rate for the polar bear populations. On the contrary, if the Arctic fox population were to decline, the polar population would increase as a result of less competitive activity for food supplies (Unger, Z., 2014). More food supplies would lead to a higher survival rate for the polar bear populations.