The polar bear is the largest predator in its habitat and requires plenty of food to sustain itself. Polar bears catch their food in different ways, and in this article, I look at the techniques they use.
Polar bears will wait by holes in the ice for seals to breathe. They can stay in total silence for hours, waiting for their prey. Polar bears stalk their prey by wading through water and camouflaging themselves.
Polar bears are expert hunters and use various strategies to ambush their prey. In this article, I explore how polar bears catch their food.
What Do Polar Bears Eat?
Polar bears are carnivores and consume the most meat out of all bear species. Their primary food source is ringed seals. Seals are an excellent food for polar bears because they are rich in fat and provide them with several days’ worth of food and energy. Polar bears get most of their nutrients from seal fat.
Although polar bears feed primarily on ringed seals, they eat hooded seals, bearded seals, harp seals, and harbor seals. They have also been seen to hunt larger animals, including narwhals, beluga whales, and walruses.
An average seal has more than one hundred thousand calories. Polar bears can measure around 2.5 meters in height and weigh 500 kilos, so they need to consume an average of sixteen thousand calories daily. To stay healthy, polar bears require at least 2 kg of fat per day.
Seals provide essential fat and blubber, a significant component in their diet, which provides the nutrients needed for the bear.
New footage from 2022 shows a polar bear chasing down and killing a reindeer in Svalbard in Norway. This was the first time that a bear had been recorded killing and eating a reindeer, as they were always thought to be too handy for them to catch.
Polar Bears Wait For Seals To Come To Them
Polar bears, although significant, can be incredibly quiet and have great patience, waiting for the perfect time to attack.
The polar bear can spend hours waiting for its prey without luck and travel many kilometers before finding food. Polar bears can catch their prey on land and in the water but prefer to hunt on ice sheets.
Seals spend up to 90% of their time under deep layers of ice, making them difficult to locate. However, ringed seals are mammals and have to breathe. When they surface, they become vulnerable to polar bears.
One of the bear’s most effective techniques for catching a seal is sitting by one of the holes in the ice that the seal uses to breathe.
The polar bear will choose between several holes that they think a seal will breathe through. The polar bear must remain completely still, avoiding sudden movements since it will alert the seal.
Seals use their whiskers connected to nerves to sense bears without seeing them. Seals can last underwater for about 10 minutes without taking a breath before they start looking for a hole in the ice.
The seal can have more than ten holes to breathe within a radius of two square kilometers, making it difficult for the bear to pinpoint where they are.
If the bear is positioned by the correct hole, it will attack when the seal emerges. Even though they are large, the bear is extremely quick. The bear has about 70 thousandths of a second to react when they see or hears the seal come out to breathe.
However, the seals have evolved a strategy not to be caught. It is evident that the bear’s reaction is swift when it is already on the surface, and the seal has very little chance of getting away. Therefore, the seal will sometimes launch an air bubble up through the hole. If a bear is at the spot, it will react instinctively and burst it.
When this happens, the seal knows that a bear is waiting and must quickly search for another vent in the ice. However, if it cannot find one when it is about to run out of air, it will return to the vent where it tried to trick the bear.
Polar Bears Are Effective at Stalking
Polar bears can conserve heat and adapt to low temperatures with their protective blubber. This allows the bear to be patient, waiting and observing its prey from a distance before approaching it silently.
Even though bears are giant, they can be reticent when stalking a seal. The bear tries to approach without the seal noticing and will attack when it is close enough. Polar bears will wait until they see their prey paying attention elsewhere.
Polar bears can wade through waters, camouflaging themselves between the ice sheets. Their color allows them to sneak up on seals effectively.
Hunting in this way is only possible when the seal decides to perch on ice blocks to rest. If the seal detects the bear but is too far away to strike, it may remain still.
What typically happens is that the bear disappears between the ice and the water, reemerging closer to the seal, giving them a chance to attack. However, this hunting technique is not always successful, as seals are very fast.
Polar bears have particular adaptations that help them succeed, including fur that breaks up their outline and transparent eyelids, allowing them to see underwater.
Their size, strength, and long claws help them overpower their prey. They will often drag their catch onto the ice, where they can eat it.
Polar Bears Are Showing New Hunting Behavior
While polar bears usually need sea ice to catch their prey, a new population of bears in Southeast Greenland is thriving in areas with little or no ice. An article in Science has uncovered a new polar bear population in Greenland.
Southeast Greenland is ice-free for over 250 days per year, and the bears in this area have adapted to living in these conditions.
A few hundred bears use fresh ice at the glacial mélange as a platform, allowing them to hunt seals all year.
With climate change affecting the sea ice and researchers believing that polar bears could soon become extinct, this behavior is exciting for the future of polar bears.
How Do Polar Bears Attack Their Prey?
Polar bears have incredibly sharp claws that can grab onto their prey so they cannot escape. Once a seal comes through a hole in the ice to breathe, the waiting bear will use their claws to kill the seal quickly. A polar bear’s claws measure up to 3.75 inches long and are incredibly sharp.
Polar bears have the most vital bite force of all bears, with a bite force of 1200 PSI, the same as a large dog or a lobster claw. They use their jaws and long teeth to grip onto their prey and can be seen thrashing it about, knocking it into the ground to hinder it.
How Much Do Polar Bears Eat In A Day?
A polar bear can eat about 30 kilos of food a day. Newborn polar bears eat much less, eating about 1 kilo a day. Polar bears can lose thousands of calories a day through walking and swimming.
Polar bears do not need to feed daily in the winter but try to eat at least once a week. The fat of a single seal is enough for a bear to survive a week, but if it hasn’t fed for over a week, it will begin to draw on its internal reserves and weaken.
When summer arrives, the polar bear will begin to use its fat reserves and eat vegetables that provide energy.
Seals have a vast sea for swimming, and the polar bear will watch them from afar once the ice melts. In the summer, polar bears have to take advantage of food such as vegetables or eggs.
In summer, the polar bear can feed several times a day if they are lucky to find food. However, food found in summer will not provide the required nutrients that a seal offers in winter.
How Many Seals Does A Polar Bear Eat?
Polar bears need to eat a seal every five to six days for its body to produce enough fat to survive each year. This is a minimum amount, but they will always look for more food so they can feed more frequently.
The fat produced by the polar bear is its main protective layer against the cold. Polar bears must constantly build up fat to not draw on their energy reserves. To sustain its body weight, a polar bear must hunt about six seals a month, equivalent to one and a quarter seals a week.
Polar bears can go without food for over 100 days, which will also seriously affect their health.
References and Further Reading
Polar Bears International – Diet and prey
WWF – Polar bear diet
Polarjournal – Researchers study reindeer hunting by polar bears
Science – A new polar bear population
Bryan Harding is a member of the American Society of Mammalogists and a member of the American Birding Association. Bryan is especially fond of mammals and has studied and worked with them around the world. Bryan serves as owner, writer, and publisher of North American Nature.