Sea Monkeys are a type of Artemia salina, which are a type of brine shrimp. Brine shrimp are a variety of fairy shrimp, or branchiopods, and are not true shrimp. The name "Sea Monkeys" is a brand name for Artemia salina to sell them as novelty gifts or toys. Generations of American children have enjoyed cultivating "families" of Sea Monkeys. They are not as popular as they once were when the fad first hit, but there is still a market for Sea Monkeys.
Sea Monkeys were first sold by Harold von Braunhut in 1957. He marketed them first called "Instant Life," and five years later, in 1962, renamed them "Sea Monkeys." Sea Monkey kits are still sold today in various forms. The original "Ocean View" tank is still sold, as well as many other Sea Monkey products. The company that makes Sea Monkeys is called Educational Insights.
In 1972, U.S. Patent number 3,673,986 was issued for "hatching brine shrimp or similar crustaceans in tap water to give the appearance of instantaneous hatching." They were advertised commonly in comic books in the 1970s. The drawings had the Sea Monkeys looking like a cross between humans, monkeys, and possibly aliens, bearing no resemblance at all to brine shrimp.
Sea Monkeys were special because in some environments that are not hard to come by, they are in a state of cryptobiosis or suspended animation which occurs naturally for them. When they are put in their aquarium the sea monkey's temporary loss of all vital functions ends, and they hatch.
When Sea Monkeys hatch, they are no larger than a small dot. They grow to be between 1/2 to 3/4 of an inch (1.27 to 1.91 cm) in length. Then they begin reproducing. Sea Monkeys are able to reproduce both asexually and sexually. There are generally more females than males born, as the males are not always needed for reproduction. They have been used in studies of sexual reproduction and DNA. Sea Monkeys generally live for about one year, but the Sea Monkey colony is sustainable for two years or longer.