Californian red worms have been utilized from the 50's in California (USA). This worm, original form Eurasia is "Eisenia Foetida". In some non scientific books was called "Red hybrid", creating a big confusion because this worms are not hybrids, they are just like the rest of nature, a result of natural selection. At this time, this breed is preferred by the majority of worm's breeders in the world because of the rusticity, tolerance to ambient factors (pH. temperature, humidity), reproductive potential, and massing capacity.