From the very first episode of Dragon Ball, we knew that Goku was no ordinary child. He had a monkey tail, was incredibly strong and could eat enough food to feed a village in one sitting. Plus, there was also the frightening giant ape transformation he went through whenever he looked at the moon. Suffice it to say, Goku's body was different from the average human's, and in Dragon Ball Z, we learned the reason behind this was that Goku wasn't a human, he was a Saiyan from the planet Vegeta. As an alien, Goku's body is much different than a human's, thus there are quite a few interesting facts pertaining to his extraterrestrial biology.
But it's not just his alien origins that make Goku's body so interesting. Goku has gone through so much over the course of the Dragon Ball franchise that the "battle scars" he's received make for some interesting stories and trivia. After countless adventures and battles, Goku's body has become a powderkeg of strength, speed, durability and power, every injury and near-death experience only serving to make his body stronger. So, what's some of the most interesting trivia about Goku's body? We've got 16 strange facts for you right here!
16 THE TALE OF HIS TAIL
Goku's tail, and Saiyan tails in general, have been pretty much abandoned in Dragon Ball, so there are a few things that fans might have forgotten about the Saiyans' fifth appendage. To start, Goku's tail, much like a monkey's, is prehensile, allowing him to use it for various tasks. In fact, it also helped Goku balance, which is why it was difficult for him to walk without it.
Goku's tail has been removed twice, first by Puar, and second by his grandpa. In between, it grew back once when he needed it most in the World Martial Arts tournament. As useful as his tail is, it also has a few drawbacks, the first being that it is incredibly sensitive, and if pulled it causes great pain. The other drawback is that it contains the glands needed for a Great Ape transformation, making it a dangerous part of his anatomy.
15 HEAD INJURY
Goku is unlike other Saiyans, he does not have the natural drive to kill, nor any natural aggression as a fighter. The reason for this is a head injury he experienced as a child. When Grandpa Gohan first took in Goku, he was aggressive and difficult to raise. But then, he experienced severe head trauma after falling off a cliff onto a rock. Surprisingly he was still alive, and after Grandpa Gohan nursed him back to health, he was completely different.
Instead of being difficult, Goku was gentle and loving, acting much like a normal baby. As he grew up, Goku showed a kind and gentle demeanor, being in tune with nature and having a love for animals. Unlike his Saiyan brethren, Goku was gentle and caring, and if he never hit his head, he might have given in to his Saiyan instincts and destroyed the planet.
Very recently, Akira Toriyama introduced the concept of S-Cells into the lore of Dragon Ball. These microscopic cells were revealed to be the key to going Super Saiyan, and where they come from lines up perfectly with the franchise's continuity. Toriyama stated that S-Cells can come from two sources: they can increase steadily when a Saiyan increases their battle power or they can come from having a gentle soul.
Because of Goku's childhood head injury, his instinctual aggressive Saiyan personality was changed into a kind and gentle one. As a result, Goku accumulated a high S-Cell count through years of caring for and protecting others. Goku's kind ways are what allowed him to be the first Super Saiyan in over 100 years, and now we know the biological reason why.
13 HIS BIOLOGICAL DRAW TO WOMEN
In Dragon Ball Super, Vegeta and Goku shared a fun moment where they both revealed how much they like their respective wives' feisty natures. Vegeta revealed that the reason for their attraction to strong-willed women actually comes from their Saiyan biology. Turns out, male Saiyans are hard-wired to choose strong women as their mates, which explains why Goku doesn't seem to mind all the times Chi-Chi has yelled at him.
Perhaps the reason behind this biological inclination for being attracted to strong women has an evolutionary purpose. Since Saiyan culture valued strong, ruthless and battle-thirsty warriors, their biology might've geared them towards choosing a feisty mate, as they would be more likely to provide stronger offspring. It's just a theory, but it would explain the reason behind Goku and Vegeta's taste in women.
12 CRAZY METABOLISM
Now this is one we're sure every Dragon Ball fan knows about: the Saiyan appetite. Even before we knew Goku was an alien, it was a recurring gag that he could pack away plates upon plates of food. This insatiable appetite followed Goku through to his adulthood and shows no signs of slowing down, save for the time he had a ki-related sickness. We would later learn this appetite is present in all Saiyans, including those who are just half-Saiyan.
The reason for such a big appetite is that Goku has a crazy metabolism, most likely to provide the energy needed to maintain his natural strength and power. In one sitting, Goku can eat enough to feed a family and still ask for seconds. His appetite has been an ongoing gag in the franchise, but it actually makes sense for his alien biology, revealing that his body needs a ton of calories to function.
11 HIS EXACT AGE?
Goku has aged incredibly weird, something that is a result of both his alien biology and the strange elements of Dragon Ball lore. Goku looked pretty much the same from the time he was 10 to his early teens, and he didn't seem to hit puberty until the final arc of Dragon Ball. From then on, Goku's appearance really hadn't changed, he still looks young and in his prime.
This is due to his Saiyan aging, which Vegeta says keeps their body in its physical prime until they're about 80, meaning he'll look and feel like he's in his early 20's for quite some time. But this isn't the only instance of weird aging, since Goku has been in the hyperbolic time chamber twice, adding four years to his life in just four days.
10 SWITCHING BODIES
We can't talk about Goku's body without mentioning the fact that it has been switched not once, but two different times. The first time came in the Namek/Frieza saga when Goku faced off against Captain Ginyu. Ginyu was a strong opponent but his true power was being able to switch bodies with people, and he did exactly that in order to gain Goku's strength. After injuring himself to cripple Goku, Ginyu used his body-switching power to switch places with Goku.
Though Goku eventually got his body back, it wouldn't be the last time he switched with someone, well at least for one version of him. In the Future Trunks saga of Dragon Ball Super, we learn that Goku Black was actually Zamasu, and he had used the super dragon balls to switch bodies with Goku, leaving Goku in the body of the Supreme Kai in training.
Like his body switching, we can't go without mentioning fusion. In Dragon Ball, there are two main types of fusion, the fusion dance and the potara earrings. In order to defeat Super Buu, Goku and Vegeta desperately use the potara to fuse into a warrior stronger than the sum of their power, Vegito. Fusion as a concept is really weird when you think about it, since the concept of sharing a fused body raises a lot of questions.
First of all, did Vegeta and Goku's minds fight for control of their body? And does Vegito love both Bulma and Chi-Chi? What do their kids call them? If you wanna get a bit more disturbing, do Goku and Vegeta remember what it's like to be a part of the same biology, meaning do they know what its like to share the same, er, "equipment?"
8 TWICE DEAD
Goku's Saiyan biology and his time in the hyperbolic time chamber aren't the only things that have weirdly affected his aging. Goku died twice over the course of Dragon Ball Z, keeping his body in otherworld due to his hero status. The first time he died, it wasn't for long, and after training with King Kai for a bit, Goku was wished back to life. The second time he died, however, he stayed dead for seven years.
During these seven years, Goku's body didn't age, making his biological age even harder to determine. Goku stayed dead for so long because the thought his presence attracted trouble to Earth, but after the Buu saga, he decided to live on Earth once again. From Goku's two death's we learned that being dead means not aging and that his body has special privileges as a hero.
7 A BIG EMPTY HOLE
Speaking of Goku dying, who can forget his first death in the early episodes of the Saiyan saga. Goku was no match for his older brother, a much more experienced Saiyan warrior, so he and Piccolo had to get rid of him the only way they could think of. Goku gave his life to hold down Raditz so that Piccolo could fire a Special Beam Cannon straight through the two of them, killing Goku almost instantly.
Though Goku's body was healed in otherworld, at the time of his death he had a massive hole right through the middle of his abdomen. We can't imagine the pain that would come with an energy attack ripping right through you, and we can see why it killed him. Ironically enough, Goku was killed by Piccolo much in the same way Goku killed King Piccolo, by piercing a hole straight through him.
6 GOD BOD
Super Saiyan God was a bit of a divergence from the other Super Saiyan forms, partially because it wasn't the next Super Saiyan form and also because it came with a lot more changes to Goku's body than just a new hairdo. All other prior Super Saiyan forms (excluding the now non-canon SS4) were pretty much a change in hair with no noticeable visual changes to Goku's body, but Super Saiyan God is different, since it turns Goku into a deity.
As a result of this divine transformation, Goku's hair and eyes turn a pinkish red, but the main changes are to his body. Goku appears to be visibly younger looking, and his muscular bulk is turned into slim definition. This change in appearance was designed to make Goku look like a youthful god, since the transformation gives him a godly ki and temporary divinity.
5 BROWS ON FLEEK
Super Saiyan 3 is the only one of the original Super Saiyan forms that changes more than Goku's hair, though the change is very minimal. The only real change that Super Saiyan 3 makes to Goku's appearance, aside from the crazy hair, is his eyebrows. That is to say that the form actually gets rid of his eyebrows, giving Goku a caveman-like appearance.
This change makes sense design-wise, as it connects the from to the ape origins of the Saiyans. Though, it does leave us with the burning question of where his eyebrows actually go when he turns Super Saiyan 3. Do they fall off? Do they recede into his brow? Or, the grossest explanation of all, does Goku grow a new brow that folds over his eyebrows? These are the real questions, people.
4 THE NOSE KNOWS
Early in Dragon Ball, it was established that Goku had a very keen sense of smell. He could track people and objects, smell food from afar and was very sensitive to strong and putrid smells. Goku's sense of smell is depicted as being similar to that of a dogs and though Goku is more like a primate than a canine, his strong nose comes from his Saiyan biology.
As useful as his sense of smell was early on, Goku doesn't seem to rely on it as much as he used to. The most likely reason for this is that ki sense became the go-to way for the Z-fighters to track and locate each other, thus making Goku's Saiyan sense of smell obsolete as both a skill and a plot device.
3 HEALING AND RECOVERY
A Saiyan's true strength is not their tail or their Great Ape forms, nor is it their Super Saiyan forms. No, it's their ability to get stronger with any battle. As such, that which doesn't kill Goku only makes him stronger. His body is capable of incredible recovery, not only healing from whatever injured him, but getting stronger to combat whatever threat hurt him in the first place.
Though there are times when Goku was out for the count, it wouldn't be long before he was back on his feet, stronger than ever before. We've seen this throughout the series, one of the first times being when Goku drank the Ultra Divine water in Dragon Ball, which almost killed him. But, as a result of this near-death experience, he came back far more powerful.
2 FUR HAIR
In the Cell Saga, when Vegeta and Future Trunks emerged from the hyperbolic time chamber, the latter's hair had grown, while Vegeta's stayed the same. Vegeta revealed the reason for this is that a full-blooded Saiyan's hair does not change from the day they are born. This is true of Goku, whose signature hair has had the same style and length since he was a kid.
Saiyans also grow facial hair, albeit very slowly, seen when Goku and Vegeta spent three years in the hyperbolic time chamber and only grew relatively short beards. Put these two facts together and Goku's hair seems a lot like the fur of an ape, which, like most mammals, grows to a certain length and then stops. This part of Goku's biology actually makes sense since Saiyans evolved from Great Ape-like creatures.
1 "COMPATIBLE PARTS"
Last but not least we come to one of the "naughtier" bits of Goku's biology, his "compatibility" with humans. Based on the fact that Goku has had two kids with Chi-Chi, a human woman, we can conclude that the reproductive biology of Saiyans is similar, if not identical to that of humans. Cleary, they were able to reproduce, meaning Goku's body is compatible enough to breed with a human woman.
Not only that, but his son was able to have a child of his own, meaning Gohan's hybrid status didn't leave him sterile like real-world cases of hybrid animals. Perhaps the most interesting part of Goku's biological compatibility with humans is that his sons have the potential to be stronger than him, since humans are a kinder species and thus create more S-Cells in a Saiyan/human hybrid offspring.