How bears move: The biomechanics of quadrupedalism
Bears locomote quadrupedally- that is, bears move around on four feet. Biomechanics is the study of structure, function, and motion in the mechanical aspects of biological systems (cells, organs, whole organisms, etcetera). In examining the biomechanics of how bears run, we can understand how this movement is efficient, how it is constrained, and ultimately, how it compares to running on two feet like humans. Bears have important physiological adaptations that allow them to handle the physical forces of running in an efficient way. A 2017 study published in the Journal of Experimental Biology observed that in bears, the scapulohumeral joint- where the upper arm bone meets the shoulder- increased energy absorption as speed increased, regardless of gait. This means that as bears transition from walking to running, their shoulder joint is able to maintain efficient energy absorption. Larger quadrupeds are also typically more efficient runners than smaller quadrupeds. Despite weighing more, larger four-legged runners are able to move more quickly than smaller species. This is because to cover the same distance, shorter limbs must have a higher stride frequency and consequently expend more energy. This allows larger animals to run faster and further. This works to a bear’s advantage because of its size. Scientists studied bears’ locomotion in controlled conditions using a treadmill and found that this assumption about large quadrupeds held true for bears with regards to greater speed. However, bears were unable to maintain these higher speeds for extensive distances.
How has running evolved in humans?
The human body has evolved to allow for efficient long-distance running more so than sprinting. A current theory amongst evolutionary anthropologists is that the ability to run long distances evolved for hunting purposes. It is thought that when human ancestors began hunting, a strategy called “persistence hunting” was employed. Persistence hunting is where the hunter attempts to outrun the prey over a long distance so they can make an easy kill when they have exhausted the target animal. Humans could not easily chase and hunt animals in a sprint, but they were able to push them to exhaustion. Other ways humans have evolved to support long distance running include an efficient cooling system and other anatomical adaptations. Humans have many sweat glands and minimal body hair. Moisture on a person’s skin from sweating allows for evaporative cooling. This is very efficient in humans due to lack of fur or substantial body hair. Many other mammals are unable to sustain running long distances because they are likely to overheat. Humans also have shorter pedal phalanges (toes) than many other animals, including other apes, which support long-distance running.
How fast can a human run?
The average sprinting speed of a human adult is 15 miles per hour. Florence Griffith-Joyner, the female world record holder in the 100-meter sprint, ran 21.3 miles per hour in her record setting race. Usain Bolt, the fastest man on earth, has a maximum recorded speed of 27.44 miles per hour.
What is the fastest species of bear?
The fastest species of bear is the American black bear. An American black bear can easily run faster than 35 miles per hour. This speed, however, cannot be sustained for long distances. Depending on the season, if a bear has its winter coat and added weight in preparation for hibernation, the bear will quickly tire and overheat. Typically, black bears travel throughout their home range walking less than 4 miles per hour. The second fastest species of bear is the grizzly bear. The maximum recorded speed of a grizzly bear is 30 miles per hour. The slowest species of bear is the polar bear. Polar bears have uniquely large paws that allow for weight distribution over a larger area. This is helpful when walking on snow and ice, similar to wearing snowshoes. These large paws also enhance a polar bears efficiency while swimming. They do, however, impede their ability to run on land. A polar bear can reach a maximum speed of 25 miles per hour on land.
Can a human outrun a bear?
A human cannot outrun a bear if being chased. All bear species could easily chase down the average human. The only scenario where a human might out-sprint a bear is if a polar bear was chasing Usain Bolt. A human can, however, outrun a bear in terms of distance. If a human was hunting or chasing a bear, they could run the bear to the point of exhaustion and catch it. If a bear were chasing a human, however, the human would stand little chance. Bears win in terms of sprinting and humans win in terms of distance.
What should you do if you encounter a wild bear?
Rather than trying to sprint away from a bear, there are other steps you can take to avoid an attack. First and foremost, before going on a hike or camping trip, research areas where there may be bears based on the season. Being informed as to where certain bears tend to wander may allow you to avoid an encounter entirely. If you do encounter a bear in the wild, remain calm. Do not attempt to charge the bear or aggress it in any way. If you are with any small children, pick them up immediately. Talk to the bear calmly in low tones so it can recognize you are a human and not a prey animal. Do not scream, imitate bear sounds or growls, or make sudden movements that may startle the bear. If they stand on their hindlegs, it is most likely out of curiosity to see you better, not an aggressive posturing. In the rare event of an attack, there are two ways to react depending on the bear species. If it is a brown bear or grizzly bear, lay on your stomach and play dead. Leave your backpack on so it can protect your torso and fold your hands on the back of your neck. Spread your legs so it is more difficult for the bear to turn you over. Remain still and the bear will likely lose interest. Retaliating against a brown bear will only escalate the intensity of the attack. If the attack continues, attempt to strike the bear in the face with whatever object is available. If attacked by a black bear, do not play dead. Try to escape to a secure location such as a car. If you cannot escape, strike the bear in the face. The fastest bear species is a black bear, which can run speeds up to 35 miles per hour. How fast can a polar bear run? Polar bears can reach a maximum speed of 25 miles per hour. This makes them slightly slower than the fastest human alive — Usain Bolt — who reached a maximum speed of 27.44 miles per hour. Polar bears are not as fast as black or brown bears because of an adaptation for larger paws that helps with winter environments. How fast can a grizzly bear run 100 yards? With grizzly bears able to sustain speeds of up to 30 miles per hour, they could cover 100 yards in 8 to 9 seconds. How fast can a Kodiak bear run? Kodiak bears can reach speeds that are similar to other brown bears across the North American continent, roughly 30 miles per hour at maximum speed. How fast can a grizzly bear run? Grizzly bears can reach top speeds of 30 miles per hour. This is slightly slower than black bears, but faster than the top speed of polar bears.
