The endometrium is the inner epithelial layer, along with its mucous membrane, of the mammalian uterus. It has a basal layer and a functional layer: the basal layer contains stem cells which regenerate the functional layer. The functional layer thickens and then is shed during menstruation in humans and some other mammals, including apes, Old World monkeys, some species of bat, the elephant shrew and the Cairo spiny mouse. In most other mammals, the endometrium is reabsorbed in the estrous cycle. During pregnancy, the glands and blood vessels in the endometrium further increase in size and number. Vascular spaces fuse and become interconnected, forming the placenta, which supplies oxygen and nutrition to the embryo and fetus. The speculated presence of an endometrial microbiota has been argued against.
The Muridae, or murids, are the largest family of rodents and of mammals, containing approximately 1,383 species, including many species of mice, rats, and gerbils found naturally throughout Eurasia, Africa, and Australia.
The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At almost 608 species, it is the second-largest family of mammals, and has members throughout the Americas, Europe and Asia.
The Old World rats and mice, part of the subfamily Murinae in the family Muridae, comprise at least 519 species. Members of this subfamily are called murines. In terms of species richness, this subfamily is larger than all mammal families except the Cricetidae and Muridae, and is larger than all mammal orders except the bats and the remainder of the rodents.
The subfamily Deomyinae consists of four genera of mouse-like rodents that were placed in the subfamilies Murinae and Dendromurinae until very recently. They are sometimes called the Acomyinae, particularly in references that antedate the discovery that the link rat, Deomys ferugineus, is part of the clade. Deomyinae is the older name and therefore has priority over Acomyinae.
The term spiny mouse refers to any species of rodent within the genus Acomys. Similar in appearance to mice of the genus Mus, spiny mice are small mammals with bare, scaled tails. However, their coats are endowed with unusually stiff guard hairs similar to the spines of a hedgehog; this trait is the source of the common name, spiny mouse.
The golden spiny mouse gets its name from the reddish-orange spiny fur that covers its body from head to tail. This coarse, inflexible fur is thought to protect it from predation. Aside from the golden fur that covers its head and upper parts, its flanks are yellow and its underside is pale. It has gray legs with pale feet and black soles. It is also described as having a small, but distinct white spot under each eye. It is often found in the wild missing a part or all of its tail because it is able to shed this as a defense mechanism. However, it is not known how this is done, how often it can occur, or under what conditions. It lives an average of three years in the wild. It is omnivorous and feeds on seeds, desert plants, snails, and insects. Living in desert regions, it is a xeric animal that obtains water from the plants that it eats and produces very concentrated urine in order to conserve water. A. russatus is naturally nocturnal, but adapts to being diurnal when it shares a habitat with A. cahirinus.
Rhabdomys is a largely Southern African genus of muroid rodents slightly larger than house mice. They are known variously as striped or four-striped mice or rats. Traditionally the genus has been seen as a single species, Rhabdomys pumilio, though modern evidence on the basis of karyotype and mtDNA analysis suggests that it comprises two or more species and subspecies. Dorsally Rhabdomys species display four characteristic black longitudinal stripes on a paler background.
The Crete spiny mouse is a species of mouse endemic to Crete. It is characterized by the coarse, stiff hairs on its back and tail and a notably grayer coloration and more pointed face than other species of spiny mice. Its fur color varies from yellow to red, gray or brown on its face and back, with white fur on its underside. It is a nocturnal forager, feeding mainly on grass blades and seeds, and builds only a very rudimentary nest.
The Western Saharan spiny mouse or Aïr spiny mouse is a species of small, insectivorous rodent in the family Muridae found arid regions of western Africa.
Chudeau's spiny mouse is a species of rodent in the family Muridae found in Mauritania and Morocco. Its natural habitats are rocky areas and hot deserts.
The Asia Minor spiny mouse is a species of rodent in the family Muridae.
The fiery spiny mouse is a species of rodent in the family Muridae found in Kenya and Tanzania. Its natural habitats are dry savanna and rocky areas. It may be found as a commensal in human habitations.
Kemp's spiny mouse is a species of rodent in the family Muridae. It is found in Kenya, Somalia, and Tanzania. Its natural habitats are dry savanna and rocky areas. It is one of only two mammals, the other being Acomys percivali, which can shed its skin. In addition, it is known to be capable of completely regenerating damaged tissue, including hair follicles, skin, sweat glands, fur and cartilage.
Percival's spiny mouse is a species of rodent in the family Muridae. It is found in Kenya, Somalia, South Sudan, and Uganda. Its natural habitats are dry savanna, subtropical or tropical dry shrubland, and rocky areas. It is one of two known species of mammals, the other being Acomys kempi, capable of completely regenerating damaged tissue, including hair follicles, skin, sweat glands, fur and cartilage.
The Cape spiny mouse is a murid rodent found in the Western Cape province of South Africa. They have a dorsal covering of spiny hairs with dark grey-brown colouration, and a white underbelly. The Cape spiny mouse has large eyes and ears and a scaly, nearly bald tail that is brittle and can break off readily either as a whole or in part if it is caught. Their total length is 17 cm (6.7 in), with an 8 cm (3.1 in) tail, and they typically weigh 22 g (0.78 oz).
Wilson's spiny mouse is a species of rodent in the family Muridae. It is found in Ethiopia, Kenya, Somalia, South Sudan, Tanzania, and Uganda. Its natural habitats are dry savanna, subtropical or tropical dry shrubland, and rocky areas.Molecular evidence suggests that spiny mice (Acomys) are genetically more closely related to gerbils (Gerbillinae) than they are to actual mice (Muridae) based on their murine morphology.
The eastern spiny mouse or Arabian spiny mouse is a species of rodent in the family Muridae. They have a wide range, having been found in Middle Eastern deserts, as well as being prevalent in riverine forests in Africa. This is the only species of spiny mouse which may have black coloration. Their diet is similar to other species of spiny mouse, consisting mostly of seeds.
Menstruation is the shedding of the uterine lining (endometrium). It occurs on a regular basis in uninseminated sexually reproductive-age females of certain mammal species.
