Goku is undoubtedly one of Dragon Ball’s strongest characters. But what secrets is the Saiyan’s body hiding?

While he isn’t exactly known for being the smartest character in Dragon Ball, Goku more than makes up for that with his strength. Even by Saiyan standards, he’s seen as a mighty warrior. Time and time again, he’s proven that he is one of the most powerful mortals this side of the multiverse.

His body has taken its fair share of beatings over the years, though, from being squeezed by giant ape Vegeta to surviving heart disease to having a laser shot through his chest. Despite all of this, he still looks young and spry, and will probably continue fighting until his body fully gives out on him. With that in mind, here are five weird facts about Goku’s body you may or may not know.

Goku’s Growth Was Stunted

When we met Goku in the first episode of Dragon Ball, he was a tiny little squirt running around the woods. But did you know that he was actually considered short, even for his young age? At the start of the series, he was around 12 years old, much to our — and Bulma’s — surprise. Many people thought he was actually younger than 10. It wasn’t until he had a couple of growth spurts between the ages of 15 and 25 that he actually started looking his age. Of course, that never stopped him from taking on opponents much bigger than him.

Goku Doesn’t Age… For A While

Despite the series spanning well over 30 years, Goku doesn’t have a single wrinkle or gray hair, while other characters around him do show signs of aging. This is because Saiyans don’t show signs of aging until they reach about 80 years old. This fact could explain why he didn’t look like he’d hit puberty until a later age. It probably also helps that his body is regenerated numerous times throughout the series. If he keeps this up, he may end up looking young for much longer than the average Saiyan. Whatever the reason is, doctors hate him.

Goku Is Able To Withstand Intense Gravity

As we see multiple times in the series, Goku’s body is able to withstand extreme levels of gravity. The first time this becomes apparent, he’s training with King Kai after being killed in his fight with Raditz. This becomes a go-to training method for him and other characters, as it increases their strength and dexterity.

The only time he seems to be in real danger is when his ship malfunctions on the way to Namek with the machine set to 100 x Earth’s gravity. Even then, he decides to keep it at this level to prepare for his fight against Frieza. It’s also implied that he and Vegeta use the Gravity Machine at Capsule Corp. for sparring in the Galactic Patrol Prisoner saga, though it’s not clear at what level they train. Vegeta has been seen training at 500 x Earth’s gravity, but there have been hints that Goku too could withstand it with some further training. Nothing can keep these boys down — not even physics.

Goku’s Hairstyle May Be Genetic

It’s not hair gel that keeps Goku’s signature hairstyle up — it seems to be genetics. When Bardock is introduced, he also sports the particular spiky hair that Goku is known for. While Gohan didn’t inherit this particular gene, Goten was lucky enough to take after dear old Dad. We even see Goku Jr., one of his descendants, with it in Dragon Ball GT’s last episode, as well as in Dragon Ball GT: A Hero’s Legacy, though the character is not considered canon within Akira Toriyama’s Dragon Ball lore.

Even his mother Gine and older brother Raditz have matching hairstyles. This begs the question, do hairstyles signify which family a Saiyan comes from — sort of like a family crest? Or is it just one of those weird anime things?

Goku’s Biggest Bodily Weakness Is… Needles

For someone as powerful as Goku, the sight of a needle should be nothing. Yet, as soon as he lays eyes on one, he’s reduced to a blubbering mess of cowardice. While not included in the manga, the phobia adds a bit of relatability to his anime counterpart. It’s never explained why he’s so scared of them, but most fears aren’t rational. Let’s just hope none of Dragon Ball‘s villains find out about it.

We’ve watched Goku grow up from a tiny 12-year-old to a towering powerhouse over the span of Dragon Ball and its sequels, and yet there are still mysteries about how his and other Saiyans’ anatomy works. Between the various power-ups and the monster appetite, it’s unclear why they, of all other alien races, make such great fighters. And even among Saiyans, Goku is still a one-off.