The Truth About Penguin Legs: Knees or No Knees?

do penguins have knees

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Penguins are flightless sea birds that are notorious for their incredible swimming skills and distinctive waddle when on land.

They can be found in the coldest and harshest environments on our planet, places such as Antarctica and sub-Antarctic islands.

If you’ve ever wondered about this bird’s leg structure and how penguins get their funny walk then you’re in the right place.

Today, we’re going to take a closer look at the penguins’ anatomy and put an end to the age-old question. Do penguins have knees?

Yes, penguins do have knees. A penguin’s leg has a short femur, knee, tibia, and fibula. Their upper leg bones are not visible as they are covered in feathers, giving the appearance that penguins do not have knees.

Do Penguins Really Have Knees?

When looking at a penguin standing on an ice cap, it may look like they have short, stumpy legs without any knees, but this is not the case.

Penguins do have knees, only they are not visible due to the thick feathers that penguins have in order to keep them warm in the freezing Arctic conditions they live in.

A penguin’s skeletal structure is laid out very similar to the birds we see in our backyards, only with a couple of adaptations to help them fly through the water instead of in the air.

One of which is the density of their bones. Most birds we see flying around in the air have hollow bones which are lightweight, allowing them to lift themselves up and into flight.

Penguins would not benefit from hollow bones as they need to be able to dive deep into the ocean in order to catch prey such as squid and fish.

Hollow bones would make penguins too buoyant and unable to dive underwater. Instead, penguins have heavy, solid bones that help give them more weight in order to dive deep.

So Why Do Penguins Waddle?

A penguin’s waddle is not for a lack of knees. Instead, it’s to save as much energy per stride as possible, an important energy-saving trait that comes in handy when food is scarce.

To find out the true reason why penguins have this distinct waddle, Timothy M. Griffin from the University of California and Rodger Kram from the University of Colorado conducted an experiment.

They coaxed Emperor penguins at San Diego Sea World to waddle across a force platform so they could measure and find out why penguins waddle.

This enabled them to measure side-to-side and back-and-forth forces as well as the vertical forces supporting the penguin’s weight.

Their hunch was that if penguins are trying to move forward, but expend energy rocking from side to side with their awkward waddle, then this has to be wasted energy.

But Kram recalls “But what we found is that they are inefficient because of their short legs and big feet, and waddling is a means to cut their losses.”

With regards to the percentage of energy saved per stride – a measure known as recovery rate – penguins actually score surprisingly well.

The human recovery rate is around 65 percent, whereas a penguin’s is up to 80 percent, among the highest of any terrestrial animal.

Griffin explained, “the penguin’s rocking motion helps raise their center of mass, and without it, their muscles would have to make up that work.”

Penguins wouldn’t have to waddle in the first place if their legs were not so diminutive, but these legs are perfectly adapted for diving and swimming.

The fact is, penguins are seabirds and don’t need to be able to run fast on land, their waddle helps them expend as little energy as possible whilst also providing them many benefits in the water.

Do Penguins Use Their Knees?

Although it may look like penguins don’t use their knees because of their distinct waddle, in actual fact, they are using their knees all of the time.

Just because we are unable to see a penguin’s knees bend as ours do, does not mean that they are not using them.

Imagine pulling an oversized t-shirt over your knees and down to your ankles, with all of your lower body essentially being invisible to the outside. This is how it is for penguins.

Their knees are very much there and working, only we don’t see it due to their feathered bodies covering them up.

A penguin’s skeletal system is different from ours, and although they don’t use their knees for walking as such, they do use them for other purposes such as incubating their eggs.

They also use their knees to slide across the ice on their stomachs. They bend their knees and push with their feet, generating force that propels them forwards on the ice.

Penguins also use their knees whilst swimming, they bend their knees for propulsion and use their feet as rudders to steer them in the right direction.

Whilst it may not look like penguins use their knees for much, in actual fact they really do. Their skeletal structure is different from ours, so they don’t rely on their knees much for walking.

However, when it comes to swimming and incubating their eggs, a penguin’s knees are crucial for these activities.

Do Penguins Have Kneecaps?

Just like we humans and many other animals, penguins do have kneecaps – also known as patellas.

A kneecap is a bone that covers the knee and helps to provide it with strength and structure, allowing the legs to bend and turn safely.

Kneecaps also provide protection for tendons and ligament structures of the knee joint and enhance the movement of the knee.

Final Thoughts

Do penguins have knees? Yes, they certainly do. A penguin’s knees are hidden externally by their feather-covered bodies, but they do have them.

However, unlike humans, penguin knees do not aid them in walking, which is why penguins are notorious for their funny-looking waddle.

That said, a penguin’s waddle is actually an effective way for them to expend less energy, which is crucial when every meal counts.

Penguin knees allow them to be the exceptional swimmers that they are, helping to propel them through the water at speeds of up to 36km/h.

Their knees are also used in incubating eggs and sliding across the ice. They are a crucial part of everyday life for penguins.

Hopefully, you’ve enjoyed this post and have learned more about penguin knees today and why they are very much important to these seabirds.

Thanks for taking the time to read this post and feel free to stick around to learn more about penguins and other marine life.