Or in this case soil? In most species the makeup of the gut is determined by genetics. However, a recent study shows that this is not true for baboons. Previously, studies have shown that the baboons' microbiota differs across populations. Researchers started to question whether this was caused by genes shared with relatives, the distance between populations or possibly the environment. How did they conduct their analysis? Well they had the dirty job of collecting poop from 14 different baboon populations all across Kenya. Not only did they collect their poop they analyzed it along with looking at 13 different characteristics of the environment of where it was collected.
As it turns out, soil has the greatest impact on the makeup of the baboons' guts. It predicted the differences of the microbiota in different populations three times better than the distance in between the populations and a whopping 15 times better than genetics. This is fascinating because it brings a whole new meaning to "you are what you eat". I didn't realize how much soil baboons consume until realizing that a lot of the leaves, fruits, seeds and insects they eat are either covering in a dusting of soil or are straight off the ground.