Why Are Wild Animals So Strong? (4 Reasons)

Why Are Wild Animals So Strong
Fact Checked and Reviewed by: Mark Rhodes, Ph.D. - Wildlife Biologist
Dr. Mark Rhodes holds an MS in Fisheries and Wildlife along with a Ph.D. in Wildlife Ecology. He helps maintain our editorial standards of accuracy and quality. You can read more about Dr. Rhodes here.

We know that animals are physically active. Birds can spend hours pumping their wings as they fly through the air, hamsters run on wheels for what seems like forever, and cheetahs are one of the fastest animals on earth because of their strong leg muscles and the way that they gallop.

But, doing these things isn’t really working out. Wild animals have the strength and stamina to do these things naturally, seemingly without any effort on their part.

So, why are wild animals so strong?

Wild animals are strong because the neurons that send messages to muscle groups control bigger groups of muscles that respond to signals from the brain. Animals also have more fast-twitch muscle fibers that allow muscles to contract faster, making them stronger. Finally, they expend their energy differently than people do.  

Below, we’ll look closer at the way that an animal’s muscle composition, number of neurons, and the way their body expends (or doesn’t expend) energy play a role in how strong they are.

Why Are Wild Animals So Strong Without Exercise?

Wild animals don’t have to work out because they are naturally strong. They have fewer muscle neurons, which allows bigger groups of muscles to respond to signals from the brain.

Additionally, their muscles are made up of more fast-twitch muscle fibers. Fast-twitch fibers expend a lot of energy in short bursts, such as when a big cat is chasing down prey. Humans, by contrast, have more short-twitch muscle fibers that are better for stamina.

Finally, they are biologically designed differently than people in the way that they expend energy and their genetic makeup. The differences are likely a big reason why animals do not lose muscle mass except in extreme scenarios.

Reason 1: Animals Have Fewer Muscle Neurons

One reason animals are stronger than humans is that animals have fewer muscle neurons than us. Neurons communicate information between your body and brain, so muscle neurons are responsible for sending signals from the brain that control your muscles.

For people to have fine motor skills, they have more muscle neurons that send information to smaller, individual muscles or muscle groups. In the case of animals, by contrast, fewer neurons control bigger muscle groups, so there is a greater response when signals are sent from the brain.

Reason 2: Animals Have Different Muscle Composition

Animal muscles are likely not the same as ours. Researchers have studied the composition of many animal muscles, including chimps, mice, and horses, and found there was a big difference in the number of slow-twitch fibers compared to fast-twitch fibers.

Slow-twitch muscle fibers contract slower when they receive signals from the brain. Since they don’t exert as much energy, they last longer and are better for endurance. For example, walking long distances or standing on your feet all day.

Fast-twitch muscle fibers, by contrast, contract quickly and have a greater output. You’d use these when running a sprint rather than a marathon because they tire more quickly.

In chimps, there is a greater composition of fast-twitch muscle fibers than those found in humans. There are also more fast-twitch muscle fibers in most animals that have been studied, including birds, cheetahs, and countless others.

Why Do Animals Have Different Muscle Composition?

In the animal kingdom, it’s really hard to answer the question of “why” anything happens. Researchers can make inferences and do experiments, but even then the results aren’t always conclusive.

That being said, one hypothesis that has been presented regarding the why of muscle composition is that animals require a faster, stronger response because of their lives in the wild and the way they are programmed for survival. Their ability to be super strong or fast may make the difference between death and survival in their day-to-day lives.

Interestingly, human muscle composition is something that changes based on the individual. The average person has about 50% slow-twitch muscle fibers and 50% fast-twitch muscle fibers. This can change in people who exercise in one way. For example, Olympic sprinters may have up to 80% fast-twitch muscle fibers in the muscles they use for running, while distance runners would have a higher concentration of slow-twitch fibers.

Reason 3: Animals Burn Energy In Short Bursts

For people, it takes a lot of lifting weights, cardio, and other exercises to burn calories and build muscle mass. Our muscles are better built for endurance than an animal’s, however, we likely don’t use the same amount of energy that they do when expending energy on a hunt. Whereas people expend energy slowly with physical activity, animals use extreme amounts of energy in short bursts.

In between hunts, animals are often seen lounging around or napping. This is because animals often don’t spend too much energy on unnecessary tasks. While they may play when bored or travel, they also have better control over the balance of their energy. So, they balance their energy output with however much energy they are putting into their body, in the form of food.

By contrast, the human body isn’t necessarily as in tune with these biological systems. So, animals are typically in better shape simply because they are able to follow the guidance of their body better when it comes to how they take in and expend energy.

Reason 4: Animal Muscles Don’t Always Atrophy Without Use

In humans, muscles atrophy without use. This basically means that if you aren’t using your muscles, your body isn’t going to waste its energy keeping them in the same shape, so they wear down over time.

Animal muscles atrophy without use too, but animals do use their muscles. The exception, of course, is when they are injured, kept in cages, or perhaps when they are hibernating.

This is likely the reason that when animals hibernate during the winter months, species like the thirteen-lined ground squirrel slow their metabolism. Some may even slow their metabolism by as much as 99% and only use 1% of the energy that they would typically.

You see, when animals are sedentary for long periods like this, their body stores nitrogen in the form of urea. The specialized microbes found in their gut break down this urea and ultimately helps fuel the body, so their bodies aren’t eating away at muscle mass during hibernation.

If it is true for hibernating mammals, it’s likely that other animals also have biological processes or things in their genetic makeup that allows them to perform great feats, even without preparing for them. For example, migrating birds travel over great distances without having to train or prepare (aside from eating food that is later stored as energy for the flight).

How Much Stronger Are Animals Than Humans?

It’s hard to say how much stronger the average animal is than a person. That being said, chimps have been closely studied for their muscle strength. In one study, it was determined that the typical chimp is about 1.5 times stronger than the average human.

Plus, an animal’s overall strength is going to depend on its muscle mass. We know that other animals don’t have the same fine motor skills as humans, so in the case of at least some of them, it’s likely that the lack of muscle neurons and greater concentration of fast-twitch fibers also play a role here.

Why Are Animals So Naturally Strong?

The simple answer is that animals are naturally strong because they are biologically different than humans. Their body composition is different in a lot of ways, but regarding strength, they have more fast-twitch muscle fibers that allow their muscles to exhibit bursts of great strength.

Additionally, they don’t have as much gray matter in their spinal cord. This is important because the amount of gray matter is linked to the number of neurons. With gray matter, animals control greater groups of muscles with fewer neurons, thus making them stronger.

Final Word

Why are wild animals so strong? It is because of the way their bodies and especially their muscles are biologically designed.

Animal muscles have a higher concentration of fast-twitch muscle fibers that allow them to exhibit extreme bursts of energy, rather than slow-twitch fibers that help with stamina. This likely helps them in fight-or-flight scenarios.

Animals also have fewer neurons that control muscles. So, a greater number of muscles respond to signals from the brain, making them stronger than the average human when you account for muscle mass.

Finally, they expend energy differently. It is not uncommon for an animal’s metabolism to change to help prevent muscle atrophy like during periods of hibernation.

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