Everyone knows you don’t need your appendix…or do you? Okay, it’s been proven by the millions of people without one that you don’t need it, but they could be missing out on some pretty important benefits to the immune system. But we’ll get to the appendix perks later. First, let’s tackle the reasoning introduced by a new study.

Scientists from all over the world just had their collective research published in Comptes Rendus Palevol, which looked at different mammals known or considered to have an appendix. Though not all scientists agree on certain species having the structure, the general consensus is that around 50 mammals have an appendix. When the researchers in the study located those 50 different species on the mammalian family tree they saw the animals were very widely distributed, so much so that they argue the appendix would have had to evolve 32 separate times in history. Those are a lot of separate evolutions for a so-called useless structure.

This led the researchers to take a closer look at the appendix itself to try and suss out what function doctors and scientists have been missing, and one happened to pop up. Aside from our own antibody-fighting cells, there are a number of endosymbiotic bacteria living in our gut that take out malicious germs. Usually the bacteria stamp out gastrointestinal insurrections fairly easily, but once in a while the bad bacteria and viruses prevail and we get sick. With murderous germs crawling all over your gut, the good bacteria need a place to hide, which researchers think might be the out-of-the-way appendix. Then when the infection subsides, the symbiotic bacteria can repopulate the intestines.

More work needs to be done on the lowly appendix, but perhaps it has a useful place in our guts after all.