Scientists have invented the first ever living robots. The robotic devices are made from the embryonic skin and heart cells of frogs. They’re known as Xenobots, getting their name from the African clawed frog, Xenopus laevis, whose stem cells are used to make the robots. This species of frogs is found in the streams and ponds of sub-Saharan Africa, where they search for food. The frogs are renowned for their claws that they use to tear the food they find.

Xenobots, developed by scientists from Tufts University and the University of Vermont, are the first-ever robots to be created entirely from living material. The machines are tiny creatures, less than a millimeter (0.04 inches) wide, and can walk and swim, survive for weeks without food, and work together in groups. They, however, can’t evolve or recreate. What’s unique about these creatures is that they can heal by themselves when wounded.