1. First, you should know that the TV series was an adaptation of a Japanese series called Kyōryū Sentai Zyuranger.
This dinosaur-themed series launched in Japan in 1992 and was adapted by the creator of Mighty Morphin Power Rangers, Haim Saban, who bought the rights for the American market. If you watch Power Rangers closely, you’ll see some fighting scenes are from the original Japanese version.
2. In this Japanese version, the Yellow Ranger was a dude.
This is why, in the American series, the Pink Ranger is often seen wearing a skirt, while the Yellow Ranger isn’t.