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>Kinda funny to think about because leaf-eaters tend to have larger more complex gut microbiomes. Your gut microbiome has been called "the second brain" because
by nobody9999 4y ago
>Kinda funny to think about because leaf-eaters tend to have larger more complex gut microbiomes. Your gut microbiome has been called "the second brain" because the majority of neurotransmitters (including over 90% of all seratonin) originates there.
Leaf eaters also tend to have larger jaw muscles and attachments for same.
That tends to limit the size of the brain case, as that space is needed for the chewing apparatus and supporting skeletal features[0].
[0] https://www.nature.com/articles/news040322-9 https://www.nature.com/articles/news040322-9
- culi 4y agoFascinating, thanks! I remember seeing a lecture by an anthropologist who showed a graph that mapped the size of different primates vs what percent of their day they spend just chewing food. Chimps spend about 60% of their days just chewing for example. The trendline was a surprisingly effective predictor for other primates. Except for humans. Based on our mass we would expect humans to spend around 70% of our day just chewing. Instead it's less than 10% Another point of evidence that supports the hypothesis put forth in the OP