Remember when you could refer to your knees as right and left? Instead of a good and a bad one? Good times, eh?
Jokes aside, knees are some of the largest and most complex joints in the body. The knees help support the body in an upright position without the need for muscles to work, allow lowering and raising of the body, and provide stability.
However, there is some confusion when it comes to the duck’s leg anatomy. Some say that ducks do not have knees. But is that really true? Do ducks have knees?
In this post, we’ll address some widespread misconceptions and explain, using simple language, the duck’s knees and how they bend.
Do Ducks Have Knees?
Yes, ducks have knees. The knees are not visible as they are covered in feathers, which might give ducks a very short-legged appearance.
People sometimes confuse the intertarsal joint on the duck’s leg for a knee.
Duck’s legs represent an interesting compromise of adaptation for efficient locomotion in two terrains, on land and on water.
Most ducks have relatively short legs and they are set far back on their body, which makes them walk awkwardly on the ground but gives them more power while swimming.
The legs in ducks are not extremely important in flight but the birds need them to provide enough force during takeoff.
A duck’s leg consists of a femur (thigh), knee (patella), tibia (drumstick), ankle (often mistaken for a knee), tarsometatarsus (foot), and digits (toes).
Like in most other birds, these bones of a duck are hollow – this enables them to fly and swim on water. If the bones were as dense as a human’s, they would be too heavy for flight.
How Do Duck Knees Bend?
The duck knees bend in the same direction as human ones, forward.
As mentioned, the joint that lots of people might consider to be the duck’s “knee” is actually the ankle joint. This joint bends backward and makes a confusion.
Their knee is higher up on the leg and does bend in the same direction ours does.
Ducks are digitigrade, which means they walk on their toes rather than their whole foot like humans.
This means that ducks walk with their weight on just their toes.
Ducks have webbed feet that allow them to swim faster and help them walk on the loose ground. They can even regulate their temperature through their feet.
How Long Legs Do Ducks Have?
Measured from the acetabulum (the socket femur inserts into) to the end of the tarsometatarsus (foot), a 5-week-old duck has a leg length of around 9.37 inches (23.79 cm).
The Pekin duck, an American breed of domestic duck that is raised primarily for meat, will almost double its leg size length during its first couple of weeks of development.
At the age of 14 days, the femur (thigh bone) is 1.92 in long; around the 21st day it is 2.33 in, and at the 32nd day of life, a duck’s femur length is 2.71 inches.
The tibia (drumstick) in 14 weeks old ducks is around 3 in long, in 3-weeks-old ducks is 3.75 in, and in 4-weeks-old ones is around 4.42 in.
In a study on hindlimbs of Pekin ducks, scientists discovered that the leg growth in these ducks begins to plateau around 5 weeks of age.
Another study on mallards (wild ducks) discovered that their leg development plateaus around 4 weeks after hatching. Their wing development, however, does not really begin until 3 weeks post-hatch.
One possible explanation for this type of hindlimb development strategy is predation – the standard predator escape mechanism for ducklings is to run to the water and swim away from the bank.
There may have been a higher selective pressure for developing legs earlier in life in the duck ancestor which would explain the patterns of leg growth in the mallard and the Pekin ducks.
Ducks Grown For Meat Will Have Leg Disorders
The rapid-growth meat birds, including ducks, have been genetically selected for the amount of mean they give. This has resulted in an increased body weight that puts stress on the immature skeleton and can cause a variety of skeletal deformities and disorders.
Some of these disorders include tibial dyschondroplasia, osteomyelitis, bone fractures, and abnormal bone deformation.
This can lead to poor gait, lameness, and eventual culling from the population, resulting in poor animal well-being.
Final Thoughts – Do Ducks Have Knees?
In conclusion, ducks do have knees. Their knees are in the upper 1/3rd of their legs and they bend forward.
Birds in general have quite long ankles, which puts the ankle joints in roughly the position we’d expect the knees to be on a human. This ankle joint in ducks bends backward and makes a lot of confusion among people.
If you were pondering on the question “do ducks have knees”, we hope this article removed all doubts.
And if you enjoyed it, here is a recommendation on other very popular bird read: Over 20 examples of birds that have white-striped wings