Japanese tradition holds that the practice of ama may be 2,000 years old. Traditionally, and even as recently as the 1960s, ama dived wearing only a loincloth. Even in modern times, ama dive without scuba gear or air tanks, making them a traditional sort of free-diver.
Ama can keep diving well into old age. The older divers are generally able to stay submerged longer than the younger. Usually they also have another job, typically working on a farm. Some Japanese people believe that the majority of ama are women because of how their bodies differ from men: The fat on a female body is distributed differently from on men.
In Pokémon Omega Ruby and Alpha Sapphire a new trainer class introduced is a Scuba-diver, however in the original Japanese translation the class is referred to as "Ama-san" and the female variation is not depicted wearing a oxygen mask or carrying oxygen tanks to reflect this.