I saw this study mentioned in the news and it really resonated with some of my own experiences since becoming a mother - as well as situations I've witnessed on the school run, problems my friends have encountered with other women and even threads on Mumsnet!
The researchers found that mothers responded more negatively to other women who had desirable assets (be that material or social) that they themselves didn't possess. In other words, women are programmed to be jealous of other women.
https://www.nature.com/articles/s41598-023-31816-0
AIBU to think this sounds pretty accurate?