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Dipodoid Rodents
Dipodoidea is a superfamily of rodents, also known as dipodoids, found across the Northern Hemisphere. This superfamily includes over 50 species among the 16 genera in 3 families. They include the jerboas (family Dipodidae), jumping mice (family Zapodidae), and birch mice (family Sminthidae). Different species are found in grassland, deserts, and forests. They are all capable of saltation (jumping while in a bipedal stance), a feature that is most highly evolved in the desert-dwelling jerboas. Taxonomy Formerly, Dipodoidea contained only a single large family, Dipodidae, which contained jerboas, jumping mice, and birch mice as subfamilies. However, phylogenetic evidence found all three to be distinct families from one another, and thus they were split into three different families within Dipodoidea. Characteristics Dipodoids are small to medium-sized rodents, ranging from in body length, excluding the tail. They are all adapted for jumping, although to varying degrees ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jaculus Orientalis
The greater Egyptian jerboa (''Jaculus orientalis'') is a species of rodent in the family Dipodidae. It is found in Algeria, Egypt, Libya, Morocco, Saudi Arabia, Tunisia, and is possibly extinct in the Negev Desert of Israel. Its natural habitats are subtropical or tropical dry shrubland, sandy shores, and arable land. Description An adult greater Egyptian jerboa has a head-and-body length of about and a tail of . The upper parts are yellowish-brown or sandy-brown and the underparts are white. The hind legs are very large and are about four times longer than the forelimbs. The feet have hairy pads which improves locomotion on sand. The tail is nearly naked but ends in a large tuft of hair which is black at the base and white at the tip. The tail is used as a prop to stabilise the animal when it stands and moves on its hind legs. Distribution and habitat On the African continent, the greater Egyptian jerboa is found in Morocco, Algeria, Tunisia, Libya and Egypt. It is also presen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seed
In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds are the product of the ripened ovule, after the embryo sac is fertilization, fertilized by Pollen, sperm from pollen, forming a zygote. The embryo within a seed develops from the zygote and grows within the mother plant to a certain size before growth is halted. The formation of the seed is the defining part of the process of reproduction in seed plants (spermatophytes). Other plants such as ferns, mosses and marchantiophyta, liverworts, do not have seeds and use water-dependent means to propagate themselves. Seed plants now dominate biological Ecological niche, niches on land, from forests to grasslands both in hot and cold climates. In the flowering plants, the ovary ripens into a fruit which contains the seed and serves to disseminate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caucasian Birch Mouse
The Caucasian birch mouse (''Sicista caucasica'') is a species of rodent in the family Sminthidae, that is endemic to Russia. Reports that it occurs in Turkey probably refer to Armenian birch mouse (''Sicista armenica''), from which it can only be reliably distinguished on the basis of karyotype. The Caucasian birch mouse inhabits the Western Montane Caucasus area, land situated between the Black Sea and the Caspian Sea The Caspian Sea is the world's largest inland body of water, described as the List of lakes by area, world's largest lake and usually referred to as a full-fledged sea. An endorheic basin, it lies between Europe and Asia: east of the Caucasus, .... References External links * Sicista Mammals of Russia Endemic fauna of Russia Taxonomy articles created by Polbot Mammals described in 1925 Taxa named by Boris Vinogradov {{rodent-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Birch Mouse
The northern birch mouse (''Sicista betulina'') is a small rodent about long (without the tail), weighing . It lives in northern Europe and Asia in forest and marsh zones. It hibernates in burrows. It eats shoots, grains, berries, and sometimes insects. Description The northern birch mouse is a small mouse with a relatively long tail. The adult head and body length is with a tail of . Adults vary in weight between . The upper parts are yellowish-grey with a brown sheen and the underparts are a pale greyish-yellow. A black stripe runs along the spine from the head to the base of the tail. Its voice is a high-pitched whistle. Distribution and habitat The northern birch mouse occurs in Scandinavia, Central and Eastern Europe, and Northern Asia. Its main range extends from the Baltic region, Poland and the Czech Republic eastwards as far as Lake Baikal in Siberia, and from the Arctic Circle southwards to the Carpathians. Isolated populations occur in Norway, Sweden, Denmark, Germ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Armenian Birch Mouse
The Armenian birch mouse (''Sicista armenica'') is a species of rodent in the family Sminthidae. Description It is a small rodent, like the mouse, the average weight of 10 g and up to 9 cm long, excluding the semi-prehensile tail, which slightly exceeds the length of the body. The body is brown, darker in the upper region. Biology The species shows nocturnal and feeds on seeds, berries and insects. Shifts in the ground with small jumps and can easily climb on the bushes and trees due to its semi-prehensile tail. The nest, oval shaped, is made of plant remains in a shallow hole dug by the animal itself. Distribution and habitat The species is endemic to Armenia, found in mixed forests of coniferous and broadleaf trees in the area upstream of the river Marmarik. Status and conservation The Zoological Society of London, on the basis of evolutionary uniqueness and smallness of the population, considers Armenian birch mouse one of the 100 species of mammal A ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sicista
Birch mice (genus ''Sicista'') are small jumping rodents that resemble mice with long, tufted tails and very long hind legs, allowing for remarkable leaps. They are the only extant members of the family Sminthidae. They are native to Eurasian forests and steppes. All variants possess a long tail of of length and weigh about . Head and body length of and hind foot length of . The animal's skin color is light brown or dark-brown to brownish yellow on the upper side and paler on the underside, but generally brownish. Birch mice have a vast geographic distribution in that they inhabit a wide variety of habitats, from semiarid areas to subalpine meadows. Although they have a diverse region of areas, their molecular and anatomical markers have claimed that Birch mice originated from Central Asia. Birch mice have a systematic of the genus of ''Sicista'', they look at the male reproductive organs and cytogenic data. Species Nineteen species are listed by the American Society of Mamm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gestation
Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregnancy can have one or more gestations at the same time, for example in a multiple birth. The time interval of a gestation is called the '' gestation period''. In obstetrics, '' gestational age'' refers to the time since the onset of the last menses, which on average is fertilization age plus two weeks. Mammals In mammals, pregnancy begins when a zygote (fertilized ovum) implants in the female's uterus and ends once the fetus leaves the uterus during labor or an abortion (whether induced or spontaneous). Humans In humans, pregnancy can be defined clinically, biochemically or biologically. Clinically, pregnancy starts from first day of the mother's last period. Biochemically, pregnancy starts when a woman's human chorionic gonado ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hibernation
Hibernation is a state of minimal activity and metabolic reduction entered by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It is most commonly used to pass through winter months – called overwintering. Although traditionally reserved for "deep" hibernators such as rodents, the term has been redefined to include animals such as bears and is now applied based on active metabolic suppression rather than any absolute decline in body temperature. Many experts believe that the processes of daily torpor and hibernation form a continuum and use similar mechanisms. The equivalent during the summer months is aestivation. Hibernation functions to conserve energy when sufficient food is not available. To achieve this energy saving, an endothermic animal decreases its metabolic rate and thereby its body temperature. Hibernation may last days, weeks, or months—depending on t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentition
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology (that is, the relationship between the shape and form of the tooth in question and its inferred function) of the teeth of an animal. Terminology Animals whose teeth are all of the same type, such as most non-mammalian vertebrates, are said to have '' homodont'' dentition, whereas those whose teeth differ morphologically are said to have '' heterodont'' dentition. The dentition of animals with two successions of teeth (deciduous, permanent) is referred to as '' diphyodont'', while the dentition of animals with only one set of teeth throughout life is ''monophyodont''. The dentition of animals in which the teeth are continuously discarded and replaced throughout life is termed '' polyphyodont''. The dentition of animals in which the teeth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diastema (dentistry)
A diastema (: diastemata, from Greek , 'space') is a space or gap between two teeth. Many species of mammals have diastemata as a normal feature, most commonly between the incisors and molars. More colloquially, the condition may be referred to as gap teeth or tooth gap. In humans, the term is most commonly applied to an open space between the upper incisors (front teeth). It happens when there is an unequal relationship between the size of the teeth and the jaw. Diastemata are common for children and can exist in adult teeth as well. In humans Causes 1. Oversized Labial Frenulum: Diastema is sometimes caused or exacerbated by the action of a labial frenulum (the tissue connecting the lip to the gum), causing high mucosal attachment and less attached keratinized tissue. This is more prone to recession or by tongue thrusting, which can push the teeth apart. 2. Periodontal Disease: Periodontal disease, also known as gum disease, can result in bone loss that supports the tee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incisor
Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, whereas armadillos, anteaters and other animals in the order Edentata have none. Structure Adult humans normally have eight incisors, two of each type. The types of incisors are: * maxillary central incisor (upper jaw, closest to the center of the lips) * maxillary lateral incisor (upper jaw, beside the maxillary central incisor) * mandibular central incisor (lower jaw, closest to the center of the lips) * mandibular lateral incisor (lower jaw, beside the mandibular central incisor) Children with a full set of deciduous teeth (primary teeth) also have eight incisors, named the same way as in permanent teeth. Young children may have from zero to eight incisors depending on the stage of their tooth eruption and tooth development. Typic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
