Comment by catfishgod on 12/03/2025 at 15:50 UTC

2 upvotes, 1 direct replies (showing 1)

View submission: Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology

Does lactose intolerance occur in any other mammals?

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Comment by bigtcm at 12/03/2025 at 16:54 UTC

14 upvotes, 1 direct replies

As a general rule, all adult mammals (including humans) are lactose intolerant. In fact, I'm pretty sure most adult humans on the planet are still lactose intolerant.

I've read that lactose tolerance (aka lactase persistance) is one of the strongest positive selective pressures that have ever evolved in humans. It turned essentially worthless grass and scrub brush into a highly nutritious food.

https://en.wikipedia.org/wiki/Lactase_persistence