Any living creature on earth needs oxygen to survive, but surprisingly, a few creatures have adapted to live without oxygen or even in extremely low-oxygen environments. These mind-blowing creatures will shock you.
1. Loricifera
These tiny marine animals, discovered in the deep, oxygen-deprived sediments of the Mediterranean Sea, have entirely abandoned the need for oxygen. Instead of mitochondria, which most animals use to produce energy with oxygen, loricifera rely on hydrogenosome-like organelles to generate energy anaerobically. This unique adaptation allows them to live in some of the most extreme environments on the planet.
2. Naked Mole Rat
The naked mole rat can survive without oxygen for up to 18 minutes, which isn’t common in warm-bodied animals. Native to the underground tunnels of East Africa, these hairless rodents have uniquely adapted to low-oxygen environments. When oxygen levels drop, naked mole rats switch from using glucose for energy to metabolizing fructose, which doesn’t require oxygen. This metabolic trick, more commonly seen in plants, allows them to endure suffocating conditions that would be fatal to most mammals.
3. Giant Tube Worm
These otherworldly creatures, which can grow over eight feet long, lack a mouth and digestive system entirely. Instead, they rely on a symbiotic relationship with chemosynthetic bacteria living inside them. These bacteria convert toxic hydrogen sulfide from the vent’s emissions into energy, allowing the tube worms to thrive in an environment that would be deadly to most life forms.
4. Earthworm
These humble creatures thrive by breathing through their skin, which must remain moist to absorb the oxygen directly from the soil. When they burrow deep into the ground, especially in waterlogged or oxygen-poor soils, earthworms rely on anaerobic respiration to meet their energy needs. This process allows them to survive in minimal oxygen levels, like flooded fields or compacted soils.
5. Brine Shrimp
These little creatures can be found in saline lakes and salt ponds and can survive without oxygen in extreme conditions. These resilient animals can enter cryptobiosis, where they effectively shut down their metabolism and become dormant in response to harsh environments, including a lack of oxygen. In this suspended animation, brine shrimp can withstand extreme temperatures, salinity, and even complete dehydration. When conditions improve, they “wake up” and resume regular activity.
6. Henneguya Salminicola
These parasitic microbes are found in salmon muscles and have evolved to live in anoxic (oxygen-free) environments, relying on anaerobic metabolism to meet their energy needs. Henneguya salminicola lacks the mitochondria typically responsible for oxygen-dependent energy production, unlike most animals. Instead, it thrives using a different biochemical process to produce energy, making it a unique example of life adapting to extreme conditions.
7. Spotted Salamander
This little critter can be found in wetlands across North America. During winter, it can enter a state of dormancy, burrowing into the mud where oxygen levels are extremely low. During this time, its bodies undergo a fascinating metabolic shift, allowing it to survive for months in an anaerobic environment.
8. Deep-Sea Mussels
These mussels live near hydrothermal vents on the ocean floor. These mussels have developed a unique way of surviving in the ocean’s dark, cold, and oxygen-poor depths. They rely on a symbiotic relationship with sulfur-oxidizing bacteria inside their gills. These bacteria convert hydrogen sulfide, a toxic gas from the vents, into energy, providing the mussels with the nutrients they need to survive without oxygen.
9. Deep-Sea Angler Fish
Found at depths of over 2,000 feet below the surface, these fish have adapted to the extreme conditions of the deep ocean, including the lack of oxygen in certain areas. Anglerfish have evolved specialized metabolic processes that allow them to survive in environments with low oxygen levels. They rely on a unique ability to extract oxygen from the surrounding water using highly efficient gills, and their slow metabolism helps them conserve energy.
10. Spinoloricus
This microscopic organism belongs to a group of worms known as loriciferans. It can survive in the anoxic, hydrogen sulphide-rich muds of the ocean floor, where oxygen levels are non-existent. Spinoloricus relies on a unique form of metabolism that doesn’t require oxygen. Instead of the typical mitochondrial processes for energy production, Spinoloricus utilizes anaerobic mechanisms.
11. Nematodes
These tiny worms are found in many environments, including oxygen-deprived soils, swamps, and deep-sea sediments. Many species of nematodes can enter a state called cryptobiosis, where their metabolism essentially shuts down, allowing them to endure environments with very little or no oxygen. Nematodes rely on anaerobic respiration, using different biochemical pathways to produce energy.
12. Venus Flytrap Sea Anemone
This anemone has evolved unique adaptations to thrive in oxygen-deprived conditions, like the sulfidic waters near hydrothermal vents. Rather than relying on oxygen, it feeds on organic matter and symbiotic bacteria that help it process nutrients in these low-oxygen environments.
