Do Penguins Have Knees? – Facts About Their Knees, Legs & Ankles

Penguin knees legs and ankles

One of the many questions that have been debated by humans is whether or not penguins have knees. After all, they don’t have any visible joints, so it’s hard to tell what their middle limbs should look like.

Contrary to popular belief, penguins do have knees. These knees are tucked up inside the body cavity, hidden by thick feathers, making it difficult to spot them. Overall, this unique anatomy contributes to the signature waddling gait of these flightless birds when walking on land.

In this article, you’ll learn more about penguin knees and how they work. To add to that, you’ll get a few fun facts regarding these avians’ legs, hips, elbows, and ankles, too. Let’s get started!

Do Penguins Really Have Knees?

Diagram of a penguin highlighting its knees
Image credit: starrcole / Pinterest

Generally speaking, penguins, with their iconic waddling walk, short legs, and webbed feet, often make people wonder about their anatomy. Yet, believe it or not, penguins have knees.

To be specific, these knee joints are part of their skeletal structure, alongside the femur, tibiotarsus, and fibula — all of which are leg bones that help these aquatic birds move around on land and in water.

However, note that penguin knees are tucked inside the body and covered with dense feathers, making them nearly invisible.

Further, when penguins walk, stand, dive, and swim, they keep their knees bent, holding their lower legs vertically. This adds to the illusion that there are no knees under their fur-like plumage.

You can also watch this video to find out where a penguin’s knees are located:

Do penguins have knees?

Do Penguins Have Kneecaps?

While not all birds maintain kneecaps, penguins stand out in this aspect; these waddling avians do possess kneecaps or patellae.

Yet, unlike with humans, penguin kneecaps are not flattened. Instead, they appear cube-shaped and are embedded within the tendon of these marine birds’ thigh muscles.

The Anatomy of a Penguin’s Legs and Knees

Penguin skeleton side view

Penguins are renowned for their exceptional aquatic abilities and distinctive waddle. A deep dive into their leg and knee anatomy can provide insights into these unique traits.

Here’s a breakdown of the anatomy of a penguin’s legs and knees:

Upper Leg

The upper part of a penguin’s leg is generally not observable as it is enveloped within the body. This part of the limb houses the thigh bones, which are shortened and adapted to help them swim efficiently in water.


As mentioned, penguins have knee joints that are not visible because they are tucked close to the body. However, these segments function in a similar way to human knees.

Further, these aquatic birds will possess two knees, each capped with a cube-shaped patella.

Lower Leg

What most consider to be a penguin’s leg is often just the lower part. It is structurally designed to support the birds’s body weight on land.

Additionally, the lower leg contains the tibiotarsus and fibula, which are bones that play a crucial role in a penguin’s movement.


Interestingly, what many usually mistake as the “knee” in a penguin’s leg is actually its ankle. This joint contains the tarsometatarsus bone and allows for added mobility.

Moreover, when combined with the foot’s structure, ankles aid in making penguins excellent swimmers.


Lastly, the feet of penguins are as important as their other body parts. Specifically, their webbed feet make it easier for them to paddle underwater, providing greater propulsion.

Why Don’t Penguins Use Their Knees?

Even if penguin legs, knees, and elbows are mostly hidden from view, bear in mind that these parts are far from unused.

In particular, penguins might appear as if they neglect their tucked-up knees, but in reality, they rely on them.

When feeling a bit lazy on land, these birds opt to slide on their stomachs, propelling themselves with their feet and leveraging their knees. Penguins also use their knees to enhance their propulsion in the water.

Overall, while penguin knees don’t bend like those of humans, they remain quite useful for these flightless birds nonetheless.

How Do Penguin Knees Function?

Penguin skeleton front view

Surprising as it may seem, the knees of penguins aren’t just there to keep their lower legs upright. These knees are actually key to an incredible number of other notable functions.

The following is a list of the most important roles penguin knees play:

  • Joint flexibility: Penguins are designed to keep their knees bent close to their bodies, almost at a 90° angle. This specific positioning allows them to maintain a low center of gravity, making their waddling motion more efficient.
  • Skeletal support: Though the tucked-up knees of penguins make their legs appear shorter, this feature actually allows them to be more steady on land.
  • Streamline body shape: Penguins are known for their streamlined forms, which is attributed to the way their knees are structured. Specifically, with their bodies close to their knees, they create a technique that minimizes swimming resistance.

In the end, while it seems like penguins have an odd relationship with their knees, it has been revealed that these specialized joints are perfectly adapted to both their aquatic and terrestrial lifestyle.

What Do Penguins Use Their Knees For?

The knees of penguins, although not immediately visible, serve a critical purpose in their daily activities. After all, without their knees, these marine birds would be unable to waddle, run, or even swim.

However, in order to get a better understanding, here is how penguins utilize their knees:

  • Efficient swimming and diving: Penguins are exceptional swimmers, and their knees have evolved to help them do so. In particular, this joint structure allows penguins to gain more thrust in water, enhancing their swimming and diving capabilities.
  • Thermoregulation: One might wonder how penguins keep warm in freezing conditions. Interestingly, their knees also assist in regulating their body temperature. They restrict or increase blood flow to these regions, which conserves or drains heat as needed.
  • Walking and waddling: On land, penguins have a distinctive walk. While it might seem comical, this movement is energy-efficient for them. Their knees facilitate this particular gait, enabling them to move on various terrains, from icy landscapes to rocky shores.
  • Maintaining posture during incubation: Reproduction is vital for the continuation of the species, and male penguins play a critical role during the incubation period. These birds use their knees as a support mechanism, resting the egg safely on their feet and covering it with their brood patch.

Based on the list above, it is evident that penguin knees have a multitude of roles. Whether aiding in swift swimming or ensuring the next generation’s safety, these animals rely heavily on their lower joints for survival.

​​Why Do Penguins Waddle When They Have Knees?

Penguin enjoying in the water side view

Since penguins spend considerable time underwater, their bodies have evolved for hydrodynamic efficiency. Yet, this adaptation has a trade-off when they’re on land: it makes them waddle.

Interestingly, however, a few studies suggest that penguins moving in a waddling gait isn’t just a quirky trait; it actually helps them save energy as they progress on land.

Fun Fact: Due to this unique movement of penguins, a group of penguins that are on the move is referred to as “a waddle of penguins.

How Do Penguins Waddle?

Penguins waddle by shifting their weight from side to side and leaning forward. This distinctive move is partly because of their large feet, body, and ankles and the fact that they don’t have long legs like most other birds.

How Fast Can Penguins Waddle?

Two happy penguins with open mouth side by side

Penguins aren’t built for speed on land. When they waddle, they move slowly, covering only approximately 1 to 2 miles per hour. This is because their bodies are designed primarily for swimming, not walking.

That said, it should be noted that penguins don’t have difficulty moving about when they need to. Although their legs are short and they cannot outrun you, they can stroll long distances if necessary.

How Far Can Penguins Waddle For?

While penguins may appear clumsy on land and even more so when they are waddling at slow speeds, they can cover vast distances between the breeding grounds and foraging areas within their icy habitats.

For instance, some species, like the Emperor penguin, can waddle an incredible 70 miles over the Antarctic terrain. The Adélie penguin follows closely, with a remarkable ability to travel over 40 miles of land.

Do Penguins Have Elbows?

Group of penguins enjoying in the Arctic

Penguins do indeed sport elbow joints. They are located where the humerus meets the radius and ulna bones. However, remember that these aren’t like the elbows you’d find in mammals.

In particular, penguins have evolved to have elbow or wing structures resembling fins, which is a trait that is superbly adapted for swimming.

Do Penguins Have Hips?

Yes, penguins possess hips. In the complex anatomy of penguins, the hip is the joint where the femur, or thigh bone, connects to the pelvis.

However, keep in mind that penguin hips are not visible as they are situated very close to these swimming birds’ tails, which is a consequence of their tucked-up knees.

Do Penguins Have Ankles?

Group of young penguins standing on the ice

Yes, penguins exhibit ankles, a feature shared with all birds.

These joints are large in size and are sometimes mistaken for knees, a misconception furthered by species like the Emperor penguin, whose ankles are covered in feathers.

Can Penguins Run?

While penguins can run, they are not speedy on land due to their short legs, managing only up to two miles per hour. Further, their preferred way of moving isn’t running but rather waddling.

During a few encounters with these swimming birds, a peculiar observation caught my attention. Most penguins chose a faster and seemingly more enjoyable method of locomotion — tobogganing.

They glide on their bellies and propel themselves forward with their flippers, almost looking like little sleds.

Frequently Asked Questions

Pair of penguins walking side by side on the ice

Why Do Penguins Fall Down So Often?

Researchers found that heavier penguins, with extra weight around their stomachs, tend to topple over more often. It’s not because they cannot bend their knees fully.

While penguins have short legs and they naturally waddle, these traits don’t impact their balance. Simply put, the added weight, not knee position, is what causes their occasional falls.

Do Penguins’ Knees Bend Backward Like Other Bird Species?

Penguins, like all birds, don’t have knees that bend backward. What seems like “backward-bending knees” on many avians are actually ankle joints.

In penguin anatomy, the actual knee is higher up, concealed by feathers, and bends similarly to human knees.

Do Penguins Injure Their Knees as They Fall Down?

Penguins don’t usually damage their knees when they fall. Unlike flying birds with lightweight, hollow bones, these marine avians possess a solid skeletal structure.

Moreover, penguins are covered in a protective, thick layer of feathers. This combination makes them sturdy and less prone to injury, even with their waddling gait and frequent tumbles.

If you’d like to share your thoughts on penguin knees and these birds’ interesting leg and ankle anatomy, feel free to waddle over to the comments section!

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