Does Anyone Have A Simplish Explanation Of Why Male Animals Tend To Be Bigger Than Females?

[Atheist]

I presume that evolution science can explain this, but I've not come across such an explanation.

[Buenchico]

Myth!

https://theconversation.com/its-a-myth-that-male-animals-are-usually-larger-than-females-new-study-225596

[bookbinder]

Myth(2)!

https://www.nhm.ac.uk/discover/news/2024/march/most-male-mammals-arent-bigger-than-females.html

[Atheist]

Buen and book. Interesting, but what makes a male different from a female, bigger or smaller, why do females follow the female body pattern and vice versa?

[wolf63]

Our friend AI says:

While not a universal rule, in many species, especially mammals, males tend to be larger than females due to sexual selection where larger males are better at competing for mates and resources, leading to greater reproductive success. 

Here's a more detailed explanation:

Sexual Selection:

In species where males compete for access to females, larger size and strength can provide an advantage in these competitions. 

Larger males are often better at defending territories, winning fights for mates, and securing resources, leading to higher reproductive success. 

Examples include male elephant seals, gorillas, and deer, where males are significantly larger than females, and this size difference is linked to their dominance and reproductive success. 

Natural Selection:

In some cases, larger size in males may also be linked to natural selection, where larger males are better adapted to exploit certain resources or survive in specific environments. 

For example, in some species, males may have evolved to be larger to better defend against predators or compete for food. 

Not a Universal Rule:

It's important to note that the trend of males being larger isn't universal. 

In some species, females are larger than males, or the sexes are similar in size. 

For example, in some bird species, females are larger and more colorful, and they are responsible for defending the territory and attracting males. 

Examples:

Mammals: Male lions, gorillas, and elephant seals are known for their significantly larger size compared to females, which is linked to their dominance and reproductive success. 

Birds: In some species, like the peacock, males are larger and more colorful, and they use these traits to attract females. 

Fish: In some species, the males are smaller than the females, and the males are responsible for guarding the eggs. 

Evolutionary Perspective:

Evolutionary biologists study sexual selection and natural selection to understand why certain traits, like size differences between sexes, have evolved in different species. 

They examine how these traits contribute to an organism's reproductive success and survival in its environment. 

[Atheist]

Thanks, Wolf, but I suppose that just as women have prominent breast and different reproductive organs, they can also have differences in their body sizes. But I still don't understand how the same species can be somehow split into two sorts. Men have small hips and bums and big arms so that they can fight, and women have big bums, weedy arms, and small upper bodies so they can reproduce and don't need to fight. I find it all puzzling how that comes about.

[wolf63]

Women may not appear to be fighters, but it is the old cat/dog anology again.

Men use their size, strength and stamina to fight.  Just like dogs.

Cats are small, agile, evil and can do a lot of damage.  Just like little pussy cats.

 

 

[Atheist]

Wolf; it's the technicalities of how different sexes of the same species are sent in different directions that puzzles me. I never did biology at school and never learned about the mechanics of evolution.

 

[Canary42]

Thanks for raising this thread Atheist, it's brought forth some interesting links/sources. 

[wolf63]

Atheist - my fault for veering your question off-course.

I have a male friend who thinks that all females are vulnerable and weak and need to be protected from everything by males.  

[Atheist]

Thanks canary and wolf.

Wolf; It seems clear to me that sex differences are not hard and fast rules - some women are physically tougher than men and vice versa; and some men are psychologically softer and weaker than women. But lots of people accept (and enjoy) simple black/white divergencies. Look at people like wotsit who tattoo and bodybuild and love to dominate women.