This is something fascinating I stumbled upon today, figured it was worth to share.
As you probably know, all animals need oxygen to survive. All, except one that is! Turns out there is one little fucker out there that can do with out it.
Meet Henneguya zschokkei, an endoparasite that afflicts several salmon species in the genera Oncorhynchus.
This is how it looks like
Yeah it's those small white lumps. Actually, that's a sack containing a bunch of them.
I know, it doesn't look like much but so far it's the only multicellular organism in the animalia kingdom that does not require oxygen to survive... At least that we know off.
Another interesting fact about these critters is that they lack both mitochondria and mitochondrial DNA. They also lack nervous, epithelial, gut and muscle cells. They are as basic as an animal can be.
They belong to the Myxosporea class of animals, which is distantly related to jellyfish, sea anemone and corals.
They are so unique that the current hypothesis is... that they originate from cancerous growths that escaped the parent organism and became a separate species:
One hypothesis put forward to explain the highly unusual habit of H. zschokkei and its fellow myxosporeans invokes the cancers of cnidarians. On this explanation, animals such as H. zschokkei were originally cancerous growths in free-swimming jellyfish that escaped their parent organism, thereafter becoming a separate species that parasitized other animals. Such an origin is referred to as a SCANDAL, a loose acronym of the phrase speciated by cancer development in animals. source
Now, that is only a theory and it may sound far fetched to you...But there are plenty of viruses that they have pulled that trick so yeah.. Not so far fetched imo. Give it enough time and evolution leads to all kind of crazy things 😄