Have you ever stopped to wonder why it is that humans have such big boobs?
They come in all shapes, sizes and colours, but they all share one thing in common... we are the only species that permanently has them.
There are another 5000+ species of mammals that roam the earth, however their breast's only appear for the purpose of feeding babies and during pregnancy.
Once the milk is gone, so are the boobs.
So why are we the only ones who have breasts?
In 1987 biologist Tim Caro explored seven existing theories. One of the most popular was that breasts allowed newborns to nurse from the hip, giving their mothers more mobility to multitask.
But that theory really doesn't explain why breasts stick around after the nursing stage is over.
Perhaps the most popular idea was first proposed by Charles Darwin and later explored by zoologist Desmond Morris in his 1967 book, "The Naked Ape."
Basically, Morris explained that breasts may have evolved as a 'sex symbol' to erm...replicate the shape of a bum while walking upright.
It's also thought they used to help males to know when a female was sexually mature. Although this doesn't but it still can't explain why they stick around after menopause.
The big difference between human breasts and those of other female mammals is that fat fills out the breast tissue, giving it shape and explains how they stay permanent.
Sadly, they can also be deadly. Breast cancer is the No. 1 cause of cancer-related deaths in women worldwide, yet as far as scientists can tell, breast cancer is not common among other primates.
Some scientists believe that this could be because the risk of cancer increases with age, and other primates don't live long enough to develop breast cancer.
In short what we've learnt here is that there really isn't an evolutionary need to have boobs.
But we're glad they're here.
