Why do mammals have mammary glands

It is a very rich food source, which varies considerably among species in composition. To cite this page: Myers, P. Espinosa, C. Parr, T. Jones, G. Hammond, and T. The Animal Diversity Web online. Disclaimer: The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe.

Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control. Mammary Glands Facebook. In the United States, 35 mammals are at risk of extinction. Get the latest on our work for biodiversity and learn how to help in our free weekly e-newsletter.

The Center for Biological Diversity is a c 3 registered charitable organization. Tax ID: Join now. For male and female mammalian embryos start out along a common developmental pathway which, for a short while, has the potential to produce either male or female anatomy. As development proceeds, sex-specific hormones kick in and channel the embryo along either the male or female route.

And the male nipple, so the general consensus goes, is simply a basic piece of mammalian anatomy that happens not to have been written out of the male developmental program. Developmental biologist Maureen Dunbar from Yale University School of Medicine and her colleagues have been finding out what causes mammary glands to develop so differently in male and female embryos.

In mouse embryos, five rudimentary buds of mammary tissue are formed in both male and female embryos very early in gestation, but in male mice this tissue starts to degenerate within a few days. In fact, in male mouse embryos the mammary buds disappear completely, leaving not even a nipple as a relic of their evanescent existence. In some other male mammals, a small part of the bud is left and it is this that forms the nipple in adult males.

In female mouse embryos the mammary buds survive, and mammary development proceeds to form both the nipples and the internal structures that will develop into functional milk-producing tissue in adult female mice.

Dunbar and colleagues have identified a tongue-twistingly-named protein as one of the key players in establishing this sexual dichotomy.

As described in the journal Development [August ], they have found that this protein, called PTHrP for short, has a dual role in male and female mammary fate. In male embryos, it is responsible for preventing the further development of the mammary bud. PTHrP produced by the bud itself stimulates the bud cells to make receptors for the? This feedback mechanism causes the mammary cells to stop developing and eventually to degenerate.

In female mouse embryos on the other hand, PTHrP acts slightly later as an essential stimulus for the mammary buds to grow and differentiate.