Tortoises are infamously slow, with pop culture, documentaries, and children’s stories making it the creatures’ most well-known trait.
Despite appearing as a disadvantage, there are genuine evolutionary benefits to the way tortoises move. Tortoises are slow because they:
- No need to hunt
- Have a slow metabolism
- Have shells for protection
These factors result in an animal that doesn’t need to move quickly. Evolution has encouraged these traits, making tortoises the slow but durable creatures that continue to thrive today.
Why Do Tortoises Walk So Slow?
Throughout nature, we see that animals have specific traits which help them survive. Nocturnal animals have good night vision, and social animals have various expressions to better communicate with others.
However, we also see odd traits that exist, not because they’re beneficial, but because there’s no evolutionary need to change them. For example, humans still have tailbones that are vestigial.
Although it would seem advantageous for tortoises to learn how to move quickly, there’s no genuine need. So, it’s theorized that tortoises never became faster because they were never forced to.
Evolutionary experts believe that tortoises don’t need to walk quickly for these reasons:
No Need To Hunt
Tortoises are foragers that spend their days eating food they find on the ground and in bushes.
Some tortoise species are omnivores and eat fish and insects but don’t hunt for food. If the insect or fish escapes, they don’t expend additional energy or time chasing after it.
Being fast is beneficial if you’re an animal surrounded by predators. Tortoises have no shortage of dangers in the wild—coyotes, foxes, badgers, and birds of prey hunt tortoises.
Naturally, you would assume that tortoises need to outrun predators, given their vulnerability. However, tortoises don’t evade their enemies by running because they’re so well-protected by their shells and burrows.
When not foraging, tortoises spend their days in burrows, which can be as deep as 50 feet underground. They’re so protected beneath the earth that other animals can’t reach them. When they go outside, they’re defended by their shells.
The same holds for tortoise vs. tortoise conflicts. These reptiles are territorial, so if you place two of them together, they’re likely to fight, especially if they’re both males. According to the Journal of Ethology, tortoises mount each other as a form of bullying.
You’d imagine that being able to run from each other to avoid harm and bullying would be beneficial. However, that’s not how tortoises respond.
Tortoises are solitary creatures and only get together to mate. Having to defend themselves from other tortoises is rare in the wild, so they use their shells for protection.
There are many evolutionary advantages to having a slow metabolism, such as the lessened release of free radicals. Free radicals accelerate aging and reduce lifespans; since tortoises release so few of them, they live longer.
However, a slow metabolism also means that tortoises often feel sluggish. Metabolism converts food into energy. Since tortoises have a low metabolic rate, their internal energy output is low.
So, it wouldn’t be beneficial for tortoises to evolve to move faster. The more an animal can move, the faster its metabolism needs to be. If tortoises had a faster metabolism, they’d release more free radicals and live shorter lifespans.
How Does the Tortoise Move?
A tortoise’s physiology makes it difficult for them to move quickly, as they’re wide in shape and their feet are far apart. Their feet are also round and stumpy, which requires them to lift each leg off the ground entirely each time they want to move forward.
They use one front leg and one back leg as an anchor when advancing. Their legs are strong, so they have no problem physically supporting their weight with two legs.
They also sway from side to side as they move. The sway is more noticeable in baby tortoises because their legs are smaller than their shells. Bigger tortoise species appear far more stable when walking since their leg muscles are bigger despite having massive shells.
Many owners worry over how much their juvenile tortoises sway and believe they’re experiencing rapid shell growth. However, swaying is normal as long as the tortoise can move forward.
How Fast Do Tortoises Move?
The average tortoises reach a maximum speed of about 0.13 to 0.30 kilometers per hour. The fastest tortoise recorded was Bertie, a leopard tortoise, which reached a top speed of 1 kilometer per hour.
How fast tortoises move depends on their size. Also, juvenile tortoises move faster than older tortoises.
How Do Tortoises Move So Slowly?
Tortoises move slowly due to their size and metabolism; the smaller the tortoise, the faster it’ll move.
Even though their legs are smaller and weaker, little tortoises weigh far less overall, so they don’t have to expend as much energy to walk.
Once tortoises grow to over 15 inches in length, they begin moving at a glacial pace. Although they have stronger muscles, they get so big that it requires more energy to move quickly.
Also, given their slow metabolism, they don’t have the energy output to advance their mass quickly.
It may seem like juvenile tortoises can move faster because they have more energy than adult tortoises, but they don’t. According to the Journal of Herpetology, juvenile tortoises expend as much energy as adult tortoises.
So, tortoises get slower as they age, not because they expend less energy over time, but because they outgrow the energy they’re capable of expending.
Can Tortoises Run?
There are moments where tortoises speed up and walk faster than usual, but it’s not considered running. Aside from their large body mass, they have other physical limitations.
Tortoises have elbows but don’t have knees; animals that run rely heavily on their hind legs to propel themselves forward. Because tortoises can’t do this, they’re unable to sprint.
Tortoises can walk a little faster than usual, depending on their circumstances. For example, a tortoise may strive for maximum speed if it can smell food nearby or feels afraid.
Are Tortoises Slower Than Turtles?
Tortoises are slower than turtles, both in water and on land. That’s partly because tortoises can’t swim, so they can’t stay afloat, let alone gain speed.
Although turtles and tortoises appear similar, turtle evolution steered itself toward moving faster than tortoises. For one, turtles dig burrows to keep themselves safe, but they’re always near water.
Turtles are faster in the water than on land, so they must reach the water to escape if they need to flee from predators.
Tortoises have stronger shells than turtles. Turtles can’t hide and protect themselves from danger as well as tortoises, so they must be able to run from danger.
Turtles also weigh less than tortoises; they have a smoother, more streamlined physiology, making swimming easier. Because their shells and legs are less heavy, they walk and run faster than tortoises, which carry too much body mass to be sprinters.
Since turtles have a greater evolutionary need to be faster runners, their legs are shaped differently than tortoises. They’re more flexible, slender, and have more joints; this added mobility allows them to propel themselves forward in ways tortoises can’t.
Are Tortoises Slower Than Sloths?
Some sloths are faster than tortoises, but it depends on the circumstances.
When feeling threatened, sloths have a max speed of 0.27 kilometers per hour. So, while sloths are faster than some tortoises, it’s only when they’re in danger.
In ordinary circumstances, sloths rarely ever move. They sleep for over 14 hours every day and only shift to stay in the shade or to reach for a leaf they can eat.
Tortoises move far more throughout the day, so they’re faster, especially if they’re young.