Does size really matter? We’ve all heard the saying and as much as
we want to disregard it as nonsense, there’s actually a scientific answer to the question. Get ready because we’ve got the truth. Evolution has driven the development of the
size and shape of the penis, and between species the proportion of penis to body size can vary
greatly. But why? Why are there different ratios of penis to
body size in animals? It all has to do with natural and sexual selection. First, we know what you’re thinking. What is the animal with the largest penis
to body ratio? Sorry human’s, but we didn’t win this
competition. The answer is... the barnacle. You heard right. The creature that lives on the sides of boats
and the rocks of beaches has the largest penis to body size proportion out of any species. Their penises can reach up to ten times the
length of their body. The reason that barnacles have such a long
penis is because they cannot move, and a mate might be a long ways away. When this happens the barnacle elongates its
penis to ten times its body size to copulate with a female counterpart. Going from small to gigantic, you may be surprised
to learn that the largest animal on the planet also has one of the largest penis to body
size proportions of the animal kingdom. Blue whales are on average 100 feet long and
the blue whale penis is between 8 to 12 feet in length. This gives it a penis to body ratio of about
10 to 1. That gives whale watching a whole new meaning. Snakes bring penis proportions to a whole
other level though. But it’s not the length or size, it's the
number that is surprising. Snakes have two penises called hemipenes. That’s right, not one, but two penises. This is because of the way snakes mate. Snakes form what is called a mating ball,
where around 100 males compete for a single female. And you thought dating apps were rough. With that kind of competition, it’s advantageous
to have a penis on either side of the body just in case the snake finds itself next to
the female. He wouldn’t want to miss his chance to mate
just because he was facing the wrong way. What if someone had a penis that was the same
size as their body? That’d be wild right? Well let us introduce you to the banana slug. It has a penis to body ratio of 1 to 1. Yes, the banana slug’s penis is the size
of its entire body. That is impressive, except for the fact that
the banana slug’s mate sometimes eats the penis after copulation. So, at that point the banana slugs raito goes
from 1 to 1 to 0 to 1. Ouch. Speaking of 0 to 1 ratios, you may be surprised
to learn that the rooster, also known as a cock, has a penis to body ratio of 0 to 1. Roosters like 97% of birds don't have a penis
outside their body at all. Instead they have what is called a cloaca,
which is a tiny nub that the rooster uses to deposit sperm into a chicken. The nicknames of animals don’t always make
sense. Or is it the other nickname that doesn’t? Other organisms not only have crazy penis
to body proportions, but crazy penis shapes. Take a pig for instance. They can have a penis to body ratio of 1 to
2, meaning their penis can be half the length of their body. But that’s not the craziest part. The pig penis is an “S” shape, ending
with a corkscrew. The shape allows male pigs to interlock with
the female during mating to make sure the job gets done. And if you think that’s wild, the tapir,
which has about the same proportion of penis to body as a pig, has been known to use its
penis to scratch its own back. Who knew the penis was such a versatile appendage? But why is there such a variety of penis proportions
and shapes? All penises have the same function, except
for maybe the tapir’s. Really though the penis has one main function
and that is to deliver the male’s sperm into the female's reproductive system, so
that the egg can be fertilized in the fallopian tube and reproduction can happen. That’s the true purpose of life in the animal
kingdom, to create offspring and pass on your genes. So why the diversity of proportions for such
a simple task? Well like everything else in biology evolution
plays an important role. If you think back to your high school science
class, evolution is the changing of species over time. More specifically, the process of natural
selection choosing which organisms have the best traits to survive and reproduce in their
environment. The penis obviously plays a role in the reproduction
of species, and therefore, evolution must have driven its development. And scientists have many different theories
as to why penis proportions vary so much between species. One surprising trait of penises is that they
are much more complicated than they should be. If the main function of the penis is to serve
as a sperm delivery system, then why is it so complicated? Well the shape and proportion of the penis
most likely evolved to ensure that successful mating occurred as often as possible. Other than dolphins, humans, and our primate
relatives, not many animals have sex just for fun or pleassure. So the shape and proportions of the penis
did not evolve to create more pleasure for the females of the species, except maybe in
humans, but more on this later. One theory as to why there are different penis
proportions is because of environmental factors in a species habitat. Species that live in high altitudes or colder
climates tend to have larger penises. This is most likely due to different mating
strategies in these regions. For example, animals like elephants and wildebeests
that live in low altitudes with warm climates tend to live in large herds. In these environments and groupings there
is much more competition between males to mate with females. Males often fight one another for access and
the right to mate. Natural selection would select for large body
size, which would help the males dominate their competitors. Once the fight has been won, it doesn’t
really matter the size of the penis, because that male has exclusive rights to mate with
the females of the herd. Therefore, in warmer regions it would seem
that large bodies and small penises are more beneficial traits to have than the other way
around. That is why species that live in warm lowland
environments tend to have smaller penis to body size ratios. On the other hand, species that live in cold
or high altitudes tend to be more solitary or isolated. This means less fighting for mates, but more
competition to make sure your sperm reaches the female’s egg first. Take the walrus. They are known to have both one of the largest
penises and penis to body size proportions out of any animal in the world. They live in the frozen arctic, which supports
relatively few individuals. Without large populations, walruses tend not
to come in contact with one another very often. That is why when sexual encounters occur it
is important that the male walrus is successful in passing on his genes. Research in walruses and other animals suggests
that the larger the penis the more likely the male is to inseminate a female. Therefore, in cold environments it is more
beneficial to have a large penis and smaller body. Successfully mating is much more important
than successfully winning a fight in these regions. Larger penises may deposit sperm closer to
the fallopian tubes thus giving those sperm a better chance of reaching the female’s
egg. Penises of the right size and shape may also
scoop out rival sperm from a different male during intercourse. Wild, we know, but in the game of reproduction,
there can only be one winner. Evidence also suggests that penis proportions
were driven by a second process of evolution as well. The name of this process is sexual selection. Sexual selection is when a specific trait
is selected for by the sexual desires of a male or female in a species. Most often it is the female of a species that
does the selecting. This trait is chosen not because it helps
the animal survive better, but because it is desirable to the opposite sex. Think of a peacock. The male peacock has extremely large vibrant
feathers. This is not a good trait to have when trying
to hide or get away from predators. But, the female peahens will typically only
mate with peacocks with the brightest, most luxurious feathers. Therefore, peacocks risk their lives for beautiful
feathers, because without them the peahens wouldn’t mate with them. No mating means no genes being passed on to
the next generation like dull feathers or penis size. So what about penis shape and proportion? Could the variety of penis proportions between
species have been caused by sexual selection? Absolutely. Different species have different traits they
find desirable. The penis is just another trait for a female
when selecting a mate. Bigger might be better, or it might not be,
it’s up to the females. Really what it comes down to is that the traits
females find most attractive are what get passed down. So for all intents and purposes females oftentimes
drive the evolution of males and this includes penis size and proportion as well. It is important to remember that animals don’t
wear clothes. That seems like a silly sentence, but stay
with us. Until recently in the evolutionary scheme
of things, even humans didn’t wear clothes. So, the penis was always hanging out for the
females of a species to see and assess. There is no hiding or denying it. No matter what you may have heard, female
preference for penis shape and proportion in the past most likely drove the variations
we see today. Now let's talk about something a little closer
to home, humans. If you are watching this video you are most
likely a human. Humans are interesting because we have big
brains and intelligence and culture. But we can’t forget that we are animals
too. Our big brains and other traits were selected
for through natural and sexual selection, just like all other living things on this
planet. When talking about male genitalia, it is interesting
to note that all human males have a larger penis to body size proportion than any of
our closest primate relatives. Yay us! Why is that though? When we compare proportions of other primates,
what we find is surprising. The largest primate, the silverback gorilla,
may be able to rip your arms off without breaking a sweat but also has the smallest penis at
just 1 inch. This is likely due to the environment and
social structure of gorillas. Since gorillas live in harems it is much more
advantageous for a gorilla to have a large body to fight off other males. Once a male proves dominance he can mate with
all the females in the harem. Therefore, there is no reason to have a large
penis as a gorilla, and in fact it would only get in the way. Our closest living relative in the animal
kingdom is the chimpanzee. Chimps have an average penis size of around
3 inches. This is over twice as large as the gorilla
and chimps are much smaller. So why the difference in proportion? And what can that tell us about humans? Well chimpanzees are notoriously promiscuous
when it comes to sex with female chimps usually having more than three mates at a time. This means that male chimps must do everything
they can to make sure their sperm fertilizes the egg first. A larger penis correlates to higher reproductive
success in chimps, either because of its ability to scoop out rival sperm or to give its sperm
a head start. So then what about us humans? Why do we have a larger proportion of penis
to body size than other primates? It would seem that human males have been placed
under heavy sexual selection by human females. Several studies have found that women prefer
a bigger penis in males. Remember, in early human history there were
no clothing, so females could always see what the males were working with. It is during this early time in human history
that females started selecting for larger penises, thus giving human males of today
a larger penis to body size proportion than other primates. It is interesting to note that recent studies
have corroborated this theory, in that on average, human females find larger penises
to be more attractive in a male. However, height and body proportions also
play a big role when females rate males on attractiveness. This suggests that not just penis size, but
the proportion of penis size to body size was selected for by females of the past. If this is the case in humans then there is
no reason to assume it isn’t true in other species as well. We are animals after all. Basically what it comes down to is that penis
to body proportions vary between species because of natural and sexual selection. The environment, mating practices, social
structure, and sexual characteristic preferences all played a role in creating the diversity
of pensies we see today. We are all part of this planet called Earth
and we are all a product of evolution. Just remember, a proportion that may be attractive
for one individual or species, might not be to another. For another video about how insane animals
are check out Strongest Animals for Their Size and Their Abilities. Or go watch What If Animals Went To World
War With Humans?
