Many have noticed the absence of a monkey tail as a distinguishing feature of the two Saiyans since their introduction into the Dragon Ball Z story (chapter 337 for Trunks and chapter 424 for Goten). There are several theories on this by the fans of the popular anime franchise.
A Distinctive Feature
How can you spot a Saiyan? These space warriors are distinguished by the appearance of a monkey tail at birth, in addition to their incredible strength and hair color change as they go through the stages of different transformations into Super Saiyans.
When they stare at the full moon, the monkey tail, which appears to be harmless, transforms them into a great ape. We first saw this tail in Dragon Ball with Son Goku, but we also saw a tail with his son Son Gohan (twice) and Vegeta during his attack on Earth in the initial episodes of Dragon Ball Z. However, upon the appearances of Trunks and Son Goten (or even Bra later), Vegeta and Goku’s respective sons, this distinguishing trait appears to be absent. Why?
Prevention Is Better Than Cure
In answer to this question, several fan theories have emerged. One of them is that their tails were simply cut off at birth, and Akira Toriyama (writer) did not draw the scenes in his illustrations. This removal of the tail protects them from becoming apes and allows them to fit in with the rest of humanity. Given the troubles brought by Gohan, it’s quite likely that Goku and his allies had the foresight to be cautious. We’re still puzzled as to why Toriyama didn’t include this information in his storyboards.
A Mistake In Overview?
Another, possibly more reasonable argument is that the mangaka just forgot to add these tails to his characters. We know that the author is known to have improvised a significant portion of the original Dragon Ball series and given his busy schedule, he may have missed some details. He recently stated, for example, that he had completely forgotten about the Super Saiyan 2 form.
Many chapters have passed between Goku’s transformation and the appearance of the androids, namely the Trunks of the Future and the child Trunks in the arms of his mother Bulma (the Namek Arc and Frieza Arc). As a result, time could be to blame for this oversight.
Problem With Genetics
When questioned, the franchise writer stated that the Saiyan tail was a recessive trait. As the mixed bloodline continues, it would eventually vanish. This would explain why Gohan has a tail but Goten does not, as well as why other “hybrid” Saiyans like Pan and Bra do not have it.
In any case, the absence appears to have little effect on the plot, and it’s uncertain whether the Saiyan tails will ever reappear.