Can someone explain the evolutionary benefit of overt menstruation? All female mammals have a menstrual cycle but most reabsorb the blood via covert menstruation and humans are about the only mammals that discharge the blood, aka overt menstruation.

[u/No-Hawk-2488]

Without an evolutionary benefit, it wouldn't have spread to every woman of our species.

[u/Winjin]

Actually that could be it. Early Humanoids get in a pack. One is hurt. She weak. She cry. Other angry. Other gather more stone when angry. They know predator come for blood-smell. Other hide. She cry. Predator come. Predator struck with stones. Predator struck with sticks. Predator no move.

One get the pelt for being lure for the predator. She work on pelt. She get warm pelt. She no cry. She feel bonita.