Some organisms can survive without oxygen. These organisms are called anaerobic organisms. Examples include protozoans, anaerobic bacteria like E-Coli, Actinomyces, Bacteroides, Clostridium, etc.
While most animals require oxygen to survive, some species have developed remarkable adaptations to survive in oxygen-deprived environments. For example, naked mole rats can survive for up to 18 minutes without oxygen by switching their bodies from using one fuel to another.
Scientists have even discovered the first multicellular animal that doesn't need oxygen to live. This groundbreaking discovery challenges the traditional definition of what an animal can be.
