Is it true that female mice can become pseudopregnant when bred with a vasectomized male?

When a female mouse is bred with a vasectomized male, she can indeed become pseudopregnant. This phenomenon occurs because the act of mating stimulates hormonal changes within the female that mimic the physiological state of pregnancy, even though the mating does not result in fertilization.

In mice, mating triggers the release of hormones such as progesterone, which prepares the uterine lining for potential implantation. As a result, the female exhibits signs of pregnancy, such as changes in behavior and physical appearance, despite not being pregnant in the traditional sense. This process is particularly notable in laboratory mice and is often utilized in research settings for various studies, including those related to reproductive biology and genetics.

It's important to understand that this response to a vasectomized male is not solely reliant on the genetic strain of the mouse, as most female mice will demonstrate this pseudopregnant response to mating. This characteristic further highlights the complexities of hormonal signaling in reproduction among rodents.