Vagina MuseumThe more common system in mammals is called an estrus cycle. Hormonally, it's very similar to a menstrual cycle, but the key difference is that animals with this form of cycle do not shed the lining of the uterus through menstruation - they reabsorb it.
GNU social JP is a social network, courtesy of GNU social JP管理人. It runs on GNU social, version 2.0.2-dev, available under the GNU Affero General Public License.
All GNU social JP content and data are available under the Creative Commons Attribution 3.0 license.