Mallard reproduction tract
Male ducks are notorious for attempting “forced copulation” with females. So females have evolved vaginas that make it hard for a male duck to actually inseminate them, if they don’t want it to, by forcing it towards the dead ends.
Most times male ducks force themselves on females, it doesn’t result in fertilization. Only 3% of duck inseminations come from forced copulation.
When a female does want to mate with a male, she will contract and relax internal muscles that scientists think help make sex easier.
The application underneath shows the female reproduction tract from the cloaca to the ovary. In most birds only the left ovary and oviduct persist. This is also the case with mallards.
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