What are Sea-Monkeys?

(Image credit: Hans Hillewaert)

Sea-Monkeys is the marketing term for a common type of sea creature: brine shrimp. As a product, Sea-Monkeys were first sold in 1950s. Sea-Monkeys are sold in packets of dust comprised of brine shrimp eggs in suspended animation. The process used to create these creatures is proprietary.

Despite their name, they're not monkeys. Sea-Monkeys are a hybrid breed of brine shrimp called Artemia NYOS produced in 1957 by Harold von Braunhut, according to the journal American Entomologist (opens in new tab). Initially marketed as "Instant Life," Sea-Monkeys are sold in hatching kits as novelty aquarium pets. 

The inspiration behind Sea-Monkeys came from a trip to a pet store, according to the Sea-Monkeys website (opens in new tab). Von Braunhut saw brine shrimp being used as fish food and wondered whether they could be used to teach children about nature. He conducted experiments to find ways to preserve the brine shrimp and then bring them back to life. 

According to EMBO Reports (opens in new tab), the creatures, which have vaguely monkey-like tails that inspire the moniker, are derived from crustaceans that undergo "cryptobiosis." Cryptobiosis is a state of suspended animation that some creatures, such as tardigrades, can enter in times of adverse environmental conditions. Creatures can stay in this state indefinitely, then reanimate when conditions improve.

A closeup of a Sea-Monkey brine shrimp. (Image credit: Nora Peevy/Getty)

When a person buys a packet of Sea-Monkeys, they appear to be lifeless dust. But when the dust is put into a tank of purified water, the Sea-Monkeys gradually emerge. They grow steadily over the next few weeks, feeding on a diet of yeast and spirulina, according to the Microscopy Society of America (MSA) (opens in new tab).

Sea-Monkeys are born with one eye, and pop out two more upon reaching maturity, according to the journal Evolutionary Biology (opens in new tab). They're translucent, and breathe through their feathery feet. They can reproduce sexually or asexually, and they chase flashlight beams. 

yellow and translucent closeup of brine shrimp eyes and antenna

A closeup of the closely related species, Artemia salina, which typically lives in highly salty environments such as brine pools. (Image credit: NNehring/Getty)

Although Sea-Monkeys are not found in nature, other brine shrimp are. Artemia NYOS are a hybrid of Artemia salina, according to the book Reproductive Biology of Crustaceans (opens in new tab)

Artemia salina live in highly salty environments, such as brine pools, according to Encyclopaedia Britannica (opens in new tab). They display similar leaflike limbs to Sea-Monkeys, which they beat to move. When they are freeze dried, Artemia salina eggs can last for several years, according to the book Medicinal Plant Research in Africa (opens in new tab)

Additional resources

You can read more about brine shrimp in this publication by the British Ecological Society (opens in new tab). Additionally, for tips about looking after Sea-Monkeys, read the Sea-Monkey Handbook (opens in new tab)

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