American researchers have created a swimming faux jellyfish out of silicone and the heart muscle cells of a rat.

The synthetic life form called the "Medusoid" contracts in salt water when stimulated with an electrical shock, according to the study published Sunday in Nature Biotechnology.

Scientists from Harvard University and the California Institute of Technology (Caltech) found real jellyfish use muscles to pump and move through water, similar to how the human heart beats.

"I was surprised that with relatively few components - a silicone base and cells that we arranged - we were able to reproduce some pretty complex swimming and feeding behaviours that you see in biological jellyfish,"

John Dabiri, a professor of aeronautics and bioengineering at Caltech, said in a statement.

Scientists hope the eight-armed artificial jellyfish will help in the research of muscular pumps and tissue engineering in humans.