How Many Knees Does A Giraffe Have? A Detailed Look At Giraffe Anatomy

Giraffes are some of the most iconic and distinctive animals in the world, easily recognized by their extremely long necks and legs. But have you ever wondered – how many knees does a giraffe have? This seemingly simple question actually leads to some fascinating insights into giraffe anatomy and evolution.

If you’re short on time, here’s a quick answer to your question: giraffes have two knees, one knee joint on each of their front and back legs just like other mammals.

In this detailed article, we’ll explore giraffe knee anatomy in depth. We’ll look at the unique adaptations that allow these gentle giants to stand so tall, compare giraffe knees to those of other mammals, and bust some common myths about giraffes and their legs.

Whether you’re a giraffe enthusiast, biology buff, or just curious, read on to learn all about the incredible knees of the giraffe!

Giraffe Leg and Knee Anatomy

Front Legs

A giraffe’s front legs are incredibly powerful and allow it to run at speeds up to 35 mph for short distances. The front legs bear around 60% of the animal’s weight and are slightly longer than the hind legs.

Each front leg contains a scapula, humerus, radius, ulna, 7 carpal bones, 3 fused metacarpal bones, and 2 cloven hooves. Giraffes have no muscles below their knees and walk by moving both legs on one side at the same time, referred to as “pacing.”

This unique gait allows them to conserve energy while moving. Their lower leg bones are quite thin and lightweight to enable swinging the leg forward rapidly when running from predators like lions. The two hooves on each foot help distribute the enormous weight pressed down on the slender limbs.

Hind Legs

The giraffe’s powerful hind legs do most of the work during running and allow it to kick with over 2,000 pounds of force. Each hind leg contains a pelvis, femur, patella, tibia, fibula, 7 tarsal bones, 3 metatarsals fused together, and 2 cloven hooves.

Their patella (kneecap) is the largest of any land mammal. Having thicker and stronger hind legs helps propel the animal forward rapidly to escape predators. Giraffes have excellent jumping ability using their robust hind limbs and have been recorded leaping distances over 5 feet high.

Their long legs enable them to easily step over obstacles while walking through thick brush in African savannas. The two hooves on each hind foot provide additional stability and weight distribution.

The Knee Joint

A giraffe’s front and hind legs both contain a single knee joint halfway down the limb. Their knee joints are unique among mammals in that they have a pair of flat, gliding bones called sesamoid bones beneath the knee cap.

These bones help reduce friction and keep the joint stable as it flexes back and forth during walking and running. Giraffes do not have any muscles below the knee, so their lower legs swing passively while pacing.

Their knee ligaments and tendons are extremely thick and tight to prevent overextension of the joint when bearing weight. The patella in their hind limb knee is proportionately the largest among land mammals since their entire body weight presses down through a single hind knee joint when standing.

Adaptations for Height

Long Legs

Giraffes have exceptionally long legs that allow them to reach heights of up to 19 feet to feed on tree leaves and shoots that other herbivores cannot access (1). Their front legs are actually longer than their back legs, with their knees located far below their body to create their distinctive silhouettes (2).

Giraffes are the tallest mammals on Earth.

Sturdy Knee Joints

To support the immense weight of these towering creatures, giraffes have very thick and sturdy knee joints. Their knee joints can measure over a foot wide (3). Extra cartilage, thick joint capsules, and collateral ligaments give their leg joints added strength and stability when bearing weight (4).

These adaptations prevent injury and dislocation when the giraffe is running or maneuvering its long legs.

Blood Pressure Regulation

Giraffes have incredibly high blood pressure compared to other mammals, with average pressures of 200/100 mm Hg in adults (5). This allows blood to travel all the way up their long necks to supply their brains.

When they lower their heads to drink, valves in their neck veins constrict to prevent excess blood flow to the brain. Their thick hide and tight skin around their legs also prevent blood pooling when standing upright for long periods.

This exceptional blood pressure control allows the giraffe to thrive at extreme heights.

So while a giraffe only has two front and two back legs like other mammals, these legs and supporting adaptations are truly exceptional! This enables the giraffe to stand out in more ways than one.

1. Giraffe Facts, Smithsonian’s National Zoo & Conservation Biology Institute
2. Giraffe, National Geographic
3. How do giraffes avoid fainting? | Science
4. The giraffe’s pressure pad: how their distinctive physiology helps control blood distribution & brain perfusion | The Journal of Physiology
5. New insights into giraffe skin adaptations | Journal of Experimental Biology

Giraffe Knees vs. Other Mammals

Quadruped vs. Biped Anatomy

Giraffes are quadruped mammals, meaning they walk on four legs. This gives them a different knee anatomy compared to biped mammals like humans that walk upright on two legs. Giraffes have two foreleg knees and two hindleg knees for a total of four knees, while humans only have two knee joints.

Large Mammals

As a large quadruped, giraffes require stout knee joints to support their tall frames and heavy bodies. An adult male giraffe can weigh over 1,900 kg and grow to 5.5 meters tall. To handle these demands, giraffes have developed thick, dense knee joints surrounded by powerful ligaments and tendons.

In contrast, human knee joints are smaller and more vulnerable to injury from excess weight and strain. But despite their toughness, giraffe knees are still susceptible to degenerative joint disease in old age like other mammals.

Differences in Leg Proportions

One of the most striking differences between giraffe and human legs are the proportions.

• Giraffes have exceptionally long legs with short thick thighs and skinny calf muscles.
• Humans have shorter legs relative to their body size, with thicker thighs and calves.

These differences in proportions allow giraffes to reach lofty heights when feeding on tree leaves, while human legs are built more for stability and strength when walking upright.

Common Myths and Misconceptions

Do Giraffes Have No Knees?

This is one of the most prevalent myths about giraffes. Many people believe that giraffes have no knees and their legs are just straight stalks. However, this is absolutely false. Giraffes do indeed have knees, they are just located much higher up on their legs than other animals.

A giraffe’s front legs can bend at the knee joint, which is located right under their body, high up on their legs. Their back legs also bend at the knee, which is located a little lower down their leg. When a giraffe is walking, their knees bend back and forth with each step.

However, when standing still a giraffe keeps its legs straight and locked in place, which makes their knees less obvious.

So why do their knees seem invisible? A key reason is that a giraffe’s legs are exceptionally long. Their knees are located nearly 5-6 feet off the ground. Plus, giraffes have no muscles below their knees, only skin and bone. This gives their lower legs a very straight appearance.

But make no mistake – those knee joints are there!

Do Giraffes Have 7 Vertebrae in their Necks?

Another common myth states that giraffes have only 7 vertebrae in their necks, just like humans. This is not true – giraffes actually have 7 cervical vertebrae, meaning vertebrae that are in the neck region. But they have a total of 33-34 vertebrae in their whole spinal column.

So why do people think they only have 7 vertebrae total? It likely stems from the fact that almost all mammals have exactly 7 cervical vertebrae in their necks. This includes relatively short-necked animals like mice and giraffes’ closest relative, the okapi.

So some people have assumed giraffes must follow this same rule.

In reality, giraffes have evolved to have remarkably long necks, with elongated cervical vertebrae. Having 7 cervical vertebrae allows flexibility and a wide range of motion in their necks. Giraffes actually have the same number of neck bones as humans do, their bones are just greatly extended to account for their amazing neck length.

Conclusion

Giraffes are incredible creatures, with evolutionary adaptations that allow them to thrive at such enormous heights. Their long, specialized legs and knees are central to supporting their huge vertical reach.

While their knee joints look different than our own, they serve the same basic functions – allowing flexion, providing stability, and bearing immense weight every time a giraffe takes a step.

Hopefully this article shed some light on giraffe anatomy while debunking common knee myths. Understanding the form and function of animal bodies reveals so much about evolution and adaptation. The next time you see a giraffe, take a moment to appreciate the amazing engineering behind those gangly, graceful legs!