Are there any living organisms that don need oxygen?
Anaerobic organisms do not require oxygen to survive. On earth, those organisms are limited to many types of bacteria and obligate anaerobes. FIRST MULTICELLULAR ANIMALS FOUND THAT CAN LIVE WITHOUT OXYGEN In the muck of the deep Mediterranean seafloor, scientists have found the first multicellular animals capable of surviving in an entirely oxygen-free environment. Some types of bacteria and other single-celled organisms can live without oxygen, but nothing as complex had been found as these three species of Loricifera, a group of marine-sediment dwellers who inhabit one of Earth’s most extreme and little-known environments.
