The manga adaptation of Genshi Shonen Ryu (原始少年リュウ Genshi shōnen Ryū) was created by Shotaro Ishinomori due to his dissatisfaction with the Genshi Shonen Ryu anime omitting various elements that were present in Ryu no Michi, particularly the futuristic and science-fiction elements. The manga consists of two volumes and follows a similar premise with Ryu looking for his mother, accompanied by the main characters from the anime, such as Ran and Don. However, the manga tells a completely different story from the anime.
- Futuristic and science-fiction elements are now present in the manga.
- Various guest characters that appeared in the anime are omitted from the manga due to the difference in its story.
- Yamu survived his encounter with the Tyranno and joins Taka in their hunt for Ryu.
- Instead of being found on the Salaman Islands, Tekedon was rescued by Ryu and his allies from the Lizards.
- Unlike the anime where Kiba serve as a mentor and father figure to Ryu, Kiba's manga counterpart is different and their relationship is more of just being allies and occasional rivals. Kiba also has an affection for Ran who reminds him of his late wife.
- Ryu and Esta's heritage are further explored, revealing that they belong to a race of humans that live in another planet.
- It is still set in the prehistoric times.
- Taka and the Tyranno still serve as the main antagonists.
- Ryu's companions are still Ran, Don, Kiba and Tekedon.
- Most the characters' appearances are mostly similar to their anime counterpart.