Mammalian reproduction relies on two important evolutionary inventions — lactation and placentation. Two recent papers shed light on how and when these important characteristics evolved. Most ...

Human animals have a simple, direct system: copulation and sperm delivery may lead to fertilization of an egg, if the timing is right. Once a sperm joins an egg, the resulting zygote gets implanted on ...

A new article in Ecological and Evolutionary Physiology examines how the immune system and reproduction interact in female mammals, especially during pregnancy, from mating to birth. Lauren E.

The new embryo enters embryonic diapause until the new-born offspring leaves the pouch nine months later. Thus, when the embryonic diapause is included, females are continuously pregnant throughout ...

This is a preview. Log in through your library . Abstract Six populations of prairie deermice were founded by releasing four males and four pregnant females into 1.9- m2 enclosures with nest boxes, ...