There’s an animal that can live without oxygen, can you believe that?  For a long time, scientists maintained an idea that seemed unquestionable, that every multicellular animal needs oxygen to live. I mean, this seems logical because without oxygen there’s no cellular respiration, and without cellular respiration there’s no energy enough for an animal organism to survive, grow or reproduce.

It’s common knowledge that oxygen is necessary for us and the planet Earth, so the fact that scientists found an animal capable of living without it is striking. They couldn’t believe what they were witnessing because it wasn’t a bacteria or anything like it, it was a multicellular animal. So let’s see what awed scientists.

Henneguya salminicola

This is the name of the protagonist of this article and the fascinating animal that struck scientists. Henneguya salminicola is a very small parasite that lives inside certain fishes. At first sight, it might not seem like a big deal because it has less than 10 cells, it doesn’t move on its own and it needs to live inside another organism to survive. However, it is a radical change in animal biology.

A special animal

What’s peculiar about Henneguya salminicola is that it doesn’t have mitochondrial genes, this means that it lacks genetic instructions so that its cells use oxygen as an energy source. Every animal that has been known, mitochondria is the one in charge of processing oxygen and nutrients to generate this energy, but the Henneguya salminicola doesn’t.

Basically, this animal does all its cycle of life without needing oxygen, something never seen before. This was something scientists couldn’t believe and they have come up with some theories.

Surviving without oxygen

What’s known about it is that it lives in marine fishes’ muscles, where oxygen is almost nonexistent, and it’s possible the Henneguya salminicola has evolved to adapt itself to that external environment.

Since it’s a parasite, it just directly takes nutrients from the organism it lives in and takes energy already processed by the fish’s cells. Also, there’s the theory of this animal having an unknown mechanism to produce the energy needed, without depending on oxygen nor mitochondria.

Importance of this finding

The Henneguya salminicola breaks one of the main principles of animal biology: the need for oxygen to live. So, this is the first evidence of an animal capable of living without it because its DNA confirmed it doesn’t have any mitochondrial genetic material.

This proves it can’t breathe in a traditional way, the one we are familiar with, but it does get the energy from other ways that haven’t been clarified yet.

Is this meaningful for the future?

Well, this finding makes scientists rethink many ideas about life. If the Henneguya salminicola can live without oxygen, it means life can adapt to conditions way more different than they thought. So, this discovery opens a window to many new questions: could exist something similar? What other ways of life could live in extreme places like the seabed?

This has been relevant for astrobiology, the science studying the possibility of life out of Earth. So, another question is set out about animals living without oxygen on other planets, with different atmospheres. If there is one on Earth, why wouldn’t the presence of this animal or a similar one that doesn’t need oxygen to live possible in other parts of the universe?

I mean, this might seem crazy but the Henneguya salminicola has already broken scientific rules showing life can be more flexible and stranger than we can imagine. So, from now on, we can expect almost anything from scientific research.