Bone Structures

Question

Hello, I am doing a research project over pelvic girdle and the difference between male and female bone structure, and comparing that to an animal, I understand that pelvic girdle is different between male and female humans, is it also different in animals? For example in a turtle, is the pubic arch more open for female turtles than male turtles? Because of birth? Or is there any other animal beside that one that I could compare? like an elephant?

Answer 1

Yes, the pelvic girdle structure can vary between male and female animals as well, just like in humans. The differences can be related to factors such as reproductive needs, mating behaviors, and the size of the animal.

In turtles, for example, female turtles have a wider and more open pubic arch than male turtles to accommodate their larger reproductive organs and facilitate egg-laying. This is also seen in other reptiles and birds, where females have wider pelvic openings compared to males.

In elephants, the differences in pelvic girdle structure between males and females are related to their size and reproductive needs. Female elephants have a wider and more bowl-shaped pelvic girdle to support their massive reproductive organs and to facilitate the birthing process, while male elephants have a narrower pelvic girdle to support their relatively smaller reproductive organs.

Other animals that can be compared in terms of pelvic girdle structure differences between males and females include primates, carnivores, and ungulates such as horses and cows.

Answer 2

To clarify/add to Naina's answer:

 

As you pointed out, humans do have very different structural differences within the pelvic girdle due to childbirth.  Females must have the wide and open pelvic inlet to allow the infant to pass through the birth canal.  Whereas males do not bear children, and therefore do not require this structural formation.  

 

However, this type of sexual dimorphism is generally only seen in bipedal humans/animals.  Because we are bipedal, we need a short and robust pelvis to bear the weight of our body.  So females need the special accommodation of a wide pelvic inlet for childbirth.  Quadrapeds (those which have four legs) are oriented horizontally and both male and females have a very elongated pelvis because of this (no need for all the weight to be on the pelvis).  There is no need for an additional widening of the pelvis for birth of live young.

 

If you want a good comparison between male/female humans and male/female animal pelvic sexual dimorphism - any quadraped or non-mammal would be a good pick.  

 

You can probably get a zoological book from the library or just google skeletal images to help explain specific points of comparison

 

Let us know if you need any further clarification!

 

Nikki B.

M.Sc. Anatomy and Forensic Anthropology

 

Answer 3

Ana,

 

Please compare human structure with a primate structure. I am assuming you are doing research project with human anatomy. Chimps,  bonobos and orangutans are closer to us in many ways and we in fact have evolved from them. Therefore, comparison is likely to be easier and would reveal significance of bipedalism, a trait that sets us apart from our animal precursors.

 

In case you are doing research project on animal anatomy then please select two organisms that are close in phylogeny. For instance, if you wish to use turtle then  use alligator/crocodile as organism to compare with.

 

Hope this helps and please post again if you have additional questions.

 

Naina B., PhD