Do penguins have knees?
The answer is yes, they really do.Yes, penguins do have knees. Their thigh bone, shin bones and knee joint are hidden inside the feather-covered body, and only the part below the ankle sticks out. That is why their legs look very short, and why they waddle when they walk on land.
The same bones as other birds
According to Kyoto City Zoo, a penguin's leg is built just like other birds' legs: a thigh bone (femur), shin bones (tibiotarsus and fibula), a bone that forms the top of the foot (tarsometatarsus), and toe bones. The New England Aquarium in the United States also explains that penguins really do have a short thigh bone, a knee and shin bones.
The knees are hidden inside the body
As Kamogawa Sea World shows with X-ray photos, the bones that match our thighs and the bones below the knee are inside the body, and only the part below the ankle sticks out. Because the knee is tucked away under the feathers inside the body, the legs look very short from the outside.
- 1Thigh bone (femur)
- 2Knee (bent, inside the body)
- 3Shin (tibiotarsus and fibula)
- 4Ankle
- 5Tarsometatarsus (top of the foot)
- 6Toe bones
A shape made for swimming
This body shape is thought to suit a life in the water. Kyoto City Zoo explains that it is the result of putting smooth swimming with less water resistance first. The Smithsonian Institution also explains that the feet, set far back on the body, work like a rudder for steering underwater and help reduce water resistance.
Why penguins waddle
The trade-off comes on land. Because the part that sticks out is so short, each step is small. Kamogawa Sea World explains that walking on such extremely short legs is what makes penguins waddle. They may look clumsy on land, but their bodies are built for swimming fast in the water.
Want to know more?
- According to the Smithsonian Institution, penguins spend up to about 75% of their lives in the water.
- The largest penguin, the emperor penguin, stands about 1.35 meters tall, while the smallest, the little penguin, is about 33 centimeters tall.
- Emperor penguins can dive as deep as about 518 meters, and a 2018 study recorded a dive lasting more than 32 minutes.
Quick quiz: test yourself
Do penguins have knees?
Show the answer
- No, they don't
- Yes, in the part you can see
- Yes, hidden inside the body
Yes, hidden inside the body The thigh bone, shin bones and knees are inside the feather-covered body, and only the part below the ankle sticks out. That is why the legs look short.
The thigh bone, shin bones and knees are inside the feather-covered body, and only the part below the ankle sticks out. That is why the legs look short.
Next quiz ›Sources
- 御意見箱に寄せられた御質問への回答（Q.ペンギンの足）京都市動物園 (in Japanese)
- Vol.258～ヨチヨチ歩きの理由～鴨川シーワールド (in Japanese)
- FAQ: Do penguins have knees?New England Aquarium
- PenguinsSmithsonian Ocean（Smithsonian Institution）
This article was written after checking the sources above as of 2026-10-03. Explanations may change as research progresses. Photo credits are shown below each photo.
