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Penile Spines
Many mammalian species have developed keratinized penile spines along the glans and/or shaft, which may be involved in sexual selection. These spines have been described as being simple, single-pointed structures (macaques) or complex with two or three points per spine (strepsirrhines). Penile spine morphology may be related to mating system. Non-human mammals Felines, especially domestic cats, are well known for having penile spines. Upon withdrawal of a cat's penis, the spines rake the walls of the female's vagina, which may serve as a trigger for ovulation. Many other felid species have penile spines, but they are relatively small in jaguars and pumas, and do not occur in margays. Penile spines in chimpanzees and mice are small surface projections made by the piling up of keratinized cell layers in the outermost skin surface.Hill, W.C.O. Note on the male external genitalia of the chimpanzee. ''Proc.Zool.Soc. Lond.'' 116, 129–132 (1946) They occur in wombats, koalas, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratin
Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, horns, claws, hooves, and the outer layer of skin among vertebrates. Keratin also protects epithelial cells from damage or stress. Keratin is extremely insoluble in water and organic solvents. Keratin monomers assemble into bundles to form intermediate filaments, which are tough and form strong unmineralized epidermal appendages found in reptiles, birds, amphibians, and mammals. Excessive keratinization participate in fortification of certain tissues such as in horns of cattle and rhinos, and armadillos' osteoderm. The only other biological matter known to approximate the toughness of keratinized tissue is chitin. Keratin comes in two types, the primitive, softer forms found in all vertebrates and harder, derived forms found only amon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammalian Species
''Mammalian Species'' is a peer-reviewed scientific journal published by Oxford University Press on behalf of the American Society of Mammalogists. The journal publishes accounts of 12–35 mammal species yearly. The articles summarize the current literature about each mammal and its systematics, genetics, fossil history, distribution, anatomy, physiology, behavior, ecology, and conservation is described. The journal was established in 1969. The current editor-in-chief is Meredith J. Hamilton (Oklahoma State University–Stillwater). See also * Journal of Mammalogy The ''Journal of Mammalogy'' is a bimonthly peer-reviewed scientific journal published by Oxford University Press on behalf of the American Society of Mammalogists. Both the society and the journal were established in 1919. The journal covers rese ... External links * Official website aOxford University Press Mammalogy journals Publications established in 1969 English-language journals {{zoo-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal Male Reproductive System
Most mammals are viviparous, giving birth to live young. However, the five species of monotreme, the platypuses and the echidnas, lay eggs. The monotremes have a sex determination system different from that of most other mammals. In particular, the sex chromosomes of a platypus are more like those of a chicken than those of a therian mammal. The mammary glands of mammals are specialized to produce milk, a liquid used by newborns as their primary source of nutrition. The monotremes branched early from other mammals and do not have the teats seen in most mammals, but they do have mammary glands. The young lick the milk from a mammary patch on the mother's belly. Viviparous mammals are in the subclass Theria; those living today are in the Marsupialia and Placentalia infraclasses. A marsupial has a short gestation period, typically shorter than its estrous cycle, and gives birth to an underdeveloped (altricial) newborn that then undergoes further development; in many species, this ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Felidae Anatomy
Felidae () is the family of mammals in the order Carnivora colloquially referred to as cats, and constitutes a clade. A member of this family is also called a felid (). The term "cat" refers both to felids in general and specifically to the domestic cat (''Felis catus''). Felidae species exhibit the most diverse fur pattern of all terrestrial carnivores. Cats have retractile claws, slender muscular bodies and strong flexible forelimbs. Their teeth and facial muscles allow for a powerful bite. They are all obligate carnivores, and most are solitary predators ambushing or stalking their prey. Wild cats occur in Africa, Europe, Asia and the Americas. Some wild cat species are adapted to forest habitats, some to arid environments, and a few also to wetlands and mountainous terrain. Their activity patterns range from nocturnal and crepuscular to diurnal, depending on their preferred prey species. Reginald Innes Pocock divided the extant Felidae into three subfamilies: the Pantheri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lion
The lion (''Panthera leo'') is a large Felidae, cat of the genus ''Panthera'' native to Africa and India. It has a muscular, broad-chested body; short, rounded head; round ears; and a hairy tuft at the end of its tail. It is sexually dimorphic; adult male lions are larger than females and have a prominent mane. It is a social species, forming groups called ''prides''. A lion's pride consists of a few adult males, related females, and cubs. Groups of female lions usually hunt together, preying mostly on large ungulates. The lion is an apex predator, apex and keystone predator; although some lions scavenge when opportunities occur and have been known to hunt Human, humans, lions typically don't actively seek out and prey on humans. The lion inhabits grasslands, savannas and shrublands. It is usually more diurnality, diurnal than other wild cats, but when persecuted, it adapts to being active nocturnality, at night and crepuscular, at twilight. During the Neolithic period, the li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Conflict
Sexual conflict or sexual antagonism occurs when the two sexes have conflicting optimal fitness strategies concerning reproduction, particularly over the mode and frequency of mating, potentially leading to an evolutionary arms race between males and females. In one example, males may benefit from multiple matings, while multiple matings may harm or endanger females, due to the anatomical differences of that species. Sexual conflict underlies the evolutionary distinction between male and female. The development of an evolutionary arms race can also be seen in the chase-away sexual selection model, which places inter-sexual conflicts in the context of secondary sexual characteristic evolution, sensory exploitation, and female resistance. According to chase-away selection, continuous sexual conflict creates an environment in which mating frequency and male secondary sexual trait development are somewhat in step with the female's degree of resistance. It has primarily been studied ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fordyce Spots
Fordyce spots (also termed Fordyce granules)James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology''. (10th ed.). Saunders. . are visible sebaceous glands that are present in most individuals. They appear on the genitals and/or on the face and in the mouth. They appear as small, painless, raised, pale, red or white spots or bumps 1 to 3 mm in diameter that may appear on the scrotum, shaft of the penis or on the labia, as well as the inner surface (retromolar mucosa) and vermilion border of the lips of the face. They are not associated with any disease or illness, nor are they infectious but rather they represent a natural occurrence on the body. No treatment is therefore required. Persons with this condition sometimes consult a dermatologist because they are worried they may have a sexually transmitted disease (especially genital warts) or some form of cancer. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird Penis
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a four-chambered heart, and a strong yet lightweight Bird skeleton, skeleton. Birds live worldwide and range in size from the bee hummingbird to the Common ostrich, ostrich. There are about ten thousand living species, more than half of which are passerine, or "perching" birds. Birds have whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the Flightless bird, loss of flight in some birds, including ratites, penguins, and diverse endemism, endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HCONDELs
hCONDELs refer to regions of deletions within the human genome containing sequences that are highly conserved among closely related relatives. Almost all of these deletions fall within regions that perform non-coding functions. These represent a new class of regulatory sequences and may have played an important role in the development of specific traits and behavior that distinguish closely related organisms from each other. Nomenclature The group of CONDELs of a specific organism is specified by prefixing the CONDELs with the first letter of the organism. For instance, hCONDELs refer to the group of CONDELs found in humans whereas mCONDELs and cCONDELs refer to mouse and chimpanzee CONDELs respectively. Identification of CONDELs The term hCONDEL was first used in the 2011 ''Nature'' article by McLean et al. in whole-genome comparison analysis. This involved firstly identifying a subset of 37,251 human deletions (hDELs) through pairwise comparisons of chimpanzee and macaque geno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hominin
The Hominini form a taxonomic tribe of the subfamily Homininae ("hominines"). Hominini includes the extant genera ''Homo'' (humans) and '' Pan'' (chimpanzees and bonobos) and in standard usage excludes the genus ''Gorilla'' (gorillas). The term was originally introduced by Camille Arambourg (1948). Arambourg combined the categories of ''Hominina'' and ''Simiina'' due to Gray (1825) into his new subtribe. Traditionally, chimpanzees, gorillas and orangutans were grouped together as pongids. Since Gray's classification, evidence has accumulated from genetic phylogeny confirming that humans, chimpanzees, and gorillas are more closely related to each other than to the orangutan. The former pongids were reassigned to the subfamily Hominidae ("great apes"), which already included humans, but the details of this reassignment remain contested; within Hominini, not every source excludes gorillas, and not every source includes chimpanzees. Humans are the only extant species in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hirsuties Coronae Glandis
Pearly penile papules (PPP) are benign small bumps on the human penis. They vary in size from 1–4 mm, are pearly or flesh-colored, smooth and dome-topped or filiform, and appear in one or several rows around the corona, the ridge of the head of the penis and sometimes on the penile shaft. They are painless, non-cancerous and not harmful. Symptoms and signs PPPs are small bumps on the human penis. They vary in size from 1–4 mm, are pearly or flesh-colored, smooth and dome-topped or filiform, and appear in one or several rows around the corona, the ridge of the glans and sometimes on the penile shaft. They are painless, non-cancerous and not harmful. Cause and mechanism PPPs are a type of angiofibroma. Their function is not well-understood. They are sometimes described as vestigial remnants of penile spines, sensitive features found in the same location in other primates. PPPs secrete oil that moistens the glans of the penis. They do not spread and often spont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galago
Galagos , also known as bush babies, or ''nagapies'' (meaning "night monkeys" in Afrikaans), are small nocturnal primates native to continental, sub-Sahara Africa, and make up the family Galagidae (also sometimes called Galagonidae). They are considered a sister group of the Lorisidae. According to some accounts, the name "bush baby" comes from either the animal's cries or its appearance. The Ghanaian name ''aposor'' is given to them because of their firm grip on branches. In both variety and abundance, the bush babies are the most successful strepsirrhine primates in Africa, according to the African Wildlife Foundation. Taxonomic classification and phylogeny Galagos are currently grouped into six genera. ''Euoticus'' is a basal sister taxon to all the other galagids. The 'dwarf' galagids recently grouped under the genus ''Galagoides'' have been found, based on genetic data, and supported by analysis of vocalisations and morphology, to actually consist of two clades, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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