The Ostrich Penis: Why Is It Unique Among Birds?

Image showing the penis of a ostrich

When you think about ostriches, the first thing that might come to mind is their size or speed, but there’s another, less-known feature that’s quite remarkable: the ostrich penis.

It’s a unique trait in the bird world, where most bird species don’t have this feature. This makes one curious: why does an ostrich have a penis when almost all other birds do not?

In this article, we’re going to take a closer look at why ostriches have this rare feature and what it means. We’ll explore what makes the ostrich’s penis so special and how it fits into the big picture of how animals live and evolve.

Do Ostriches Have Penises?

Penis of ostrich before mating

Ostriches stand out in the bird world as they are one of the very few types of birds that have penises. In fact, only about 3% of all bird species have penises.

Most birds mate in a simple way, where the male and female birds just sort of press their cloacas together to transfer sperm.

But ostriches are different. The presence of a penis in ostriches allows for a more direct transfer of sperm to the female, which can be beneficial for successful fertilization.

The fact that having a penis is so rare in birds makes the ostrich’s reproductive anatomy a subject of interest in ornithological and evolutionary studies.

What Does an Ostrich Penis Look Like?

Close up of ostrich penis

In birds, the term “penis” has a slightly different meaning compared to mammals.

For ostriches, it refers to an elongated structure that extends from the cloaca, which is their all-in-one opening for both excretion and reproduction.

An ostrich’s penis has a cone-like shape, being wider at the bottom and then narrowing towards the top. Also, it has a noticeable bend towards the left and is bright red in color.

The penis of an adult male ostrich measures around 10 to 12 inches (25-30 cm) in length and is very robust, which is consistent with their large size.

Ostriches keep their penises tucked inside their bodies when not mating, extending them from the cloaca only when needed. And unlike mammals, they don’t use blood to make their penises erect.

Instead, these are filled with a type of body fluid called lymph. This makes their penises quite different in both appearance and function.

Why Do Ostriches Have Penises, Unlike Most Birds?

Male ostrich with a visible penis

While the exact reason why ostriches have penises is not entirely clear, scientific studies have shed some light on this question.

A study comparing the embryonic development of birds with and without penises found that the Bmp4 gene plays a key role.

During the development of bird embryos, a gene called Bmp4 activates in most bird species, which causes the cells at the tips of their developing penises to die off. This results in the absence of a penis in adult birds.

However, in ostriches, this Bmp4 gene is switched off, allowing their penises to grow to full size. This is the same case for species like ducks and emus, which also have penises.

Now, regarding why these birds evolved to keep their penises, scientists believe it could be linked to how they mate and have babies.

Each bird species has its own way of doing things, and having a penis might just be more helpful for ostriches in their natural environment.

That said, it’s important to note that this is still a topic of ongoing research and discussion in the scientific community. So, there’s more to learn about why ostriches and some other birds are different in this way.

How Do Ostriches Mate?

Ostriches mating in the wild

Ostriches mate in a way that’s slightly different from most birds, largely because male ostriches have penises.

While most birds mate using a “cloacal kiss,” where they press their cloacas together, ostriches use direct sperm transfer. This method differs in that it doesn’t rely much on the female’s cooperation for successful mating.

I once had the chance to witness this in person during a trip to OstrichLand, and it was an unforgettable experience.

The male ostrich performed an elaborate dance to attract females, which involved feather fluffing, wing flapping, and head swinging.

I then saw how a female ostrich signals its readiness to mate. The female spread its wings wide and crouched low to the ground. In response, the male approached and carefully mounted the female.

It was fascinating to see how it balanced, keeping one foot on the ground and the other on the female’s back.

If you want to see this incredible mating ritual for yourself, check out this video:

Ostrich Gives the Performance of His Life | The Mating Game | BBC Earth

Do Ostriches Have Testes?

Yes, ostriches do have testes. In fact, male ostriches have two testes, each located on either side of their body, inside the abdominal cavity, right above the kidneys.

Unlike many mammals, whose testes are external, ostriches’ testes are inside their bodies.

Their testes are pretty big, about the size of a baseball. During the breeding season, these testes get even bigger, growing about two to three times their normal size.

This size suggests that ostriches can produce a large number of sperm, which aids in successful mating and fertilization.

Fun Fact: Male ostriches’ sperm production is highly sensitive to temperature changes. The optimal temperature for ostrich reproduction is around 20 to 25°C.

When the temperature deviates from this range, it can significantly impact sperm and egg production. In fact, just a 5°C change in temperature can lead to a drastic reduction in reproductive success of up to 40%!

So, do you have any questions or thoughts about the ostrich penis or its role in the bird’s life? Feel free to share them in the comments below, and let’s keep the conversation going!

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