There is a book somewhere that talks about this in detail, its not just animals, but in third world countries, people don't sit with their legs and back at ~90

There is a book somewhere that talks about this in detail, its not just animals, but in third world countries, people don't sit with their legs and back at ~90 degree angles. Chairs are actually the most unnatural position for our bodies as a sedentary position (especially in the case of toilets while defecating). There are a lot of back and other problems that come with prolonged use of chairs that simply don't occur in areas of the world where people squat or don't have chairs.