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Seasonal Breeder
Seasonal breeders are animal species that successfully mate only during certain times of the year. These times of year allow for the optimization of survival of young due to factors such as ambient temperature, food and water availability, and changes in the predation behaviors of other species. Related sexual interest and behaviors are expressed and accepted only during this period. Female seasonal breeders will have one or more estrus cycles only when she is "in season" or fertile and receptive to mating. At other times of the year, they will be anestrus, or have a dearth of their sexual cycle. Unlike reproductive cyclicity, seasonality is described in both males and females. Male seasonal breeders may exhibit changes in testosterone levels, testes weight, and fertility depending on the time of year. Seasonal breeders are distinct from opportunistic breeders, that mate whenever the conditions of their environment become favorable, and continuous breeders that mate year-rou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal
Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, have myocytes and are motility, able to move, can reproduce sexually, and grow from a hollow sphere of Cell (biology), cells, the blastula, during embryonic development. Animals form a clade, meaning that they arose from a single common ancestor. Over 1.5 million extant taxon, living animal species have been species description, described, of which around 1.05 million are insects, over 85,000 are molluscs, and around 65,000 are vertebrates. It has been estimated there are as many as 7.77 million animal species on Earth. Animal body lengths range from to . They have complex ecologies and biological interaction, interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luteinizing Hormone
Luteinizing hormone (LH, also known as luteinising hormone, lutropin and sometimes lutrophin) is a hormone produced by gonadotropic cells in the anterior pituitary gland. The production of LH is regulated by gonadotropin-releasing hormone (GnRH) from the hypothalamus. In females, an acute rise of LH known as an LH surge, triggers ovulation and development of the corpus luteum. In males, where LH had also been called interstitial cell–stimulating hormone (ICSH), it stimulates Leydig cell production of testosterone. It acts synergistically with follicle-stimulating hormone ( FSH). Etymology The term luteinizing comes from the Latin "luteus", meaning "yellow". This is in reference to the corpus luteum, which is a mass of cells that forms in an ovary after an ovum (egg) has been discharged. The corpus luteum is so named because it often has a distinctive yellow color. The process of forming the corpus luteum is known as " luteinization", and thus the hormone that triggers th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethology
Ethology is a branch of zoology that studies the behavior, behaviour of non-human animals. It has its scientific roots in the work of Charles Darwin and of American and German ornithology, ornithologists of the late 19th and early 20th century, including Charles Otis Whitman, Charles O. Whitman, Oskar Heinroth, and Wallace Craig. The modern discipline of ethology is generally considered to have begun during the 1930s with the work of the Dutch biologist Nikolaas Tinbergen and the Austrian biologists Konrad Lorenz and Karl von Frisch, the three winners of the 1973 Nobel Prize in Physiology or Medicine. Ethology combines laboratory and field science, with a strong relation to neuroanatomy, ecology, and evolutionary biology. Etymology The modern term ''ethology'' derives from the Greek language: wikt:ἦθος, ἦθος, ''ethos'' meaning "character" and , ''wikt:-logia, -logia'' meaning "the study of". The term was first popularized by the American entomologist William Mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Breeding
Animal breeding is a branch of animal science that addresses the evaluation (using best linear unbiased prediction and other methods) of the genetic value (estimated breeding value, EBV) of livestock. Selecting for breeding animals with superior EBV in growth rate, egg, meat, milk, or wool production, or with other desirable traits has revolutionized livestock production throughout the entire world. The scientific theory of animal breeding incorporates population genetics, quantitative genetics, statistics, and recently molecular genetics and is based on the pioneering work of Sewall Wright, Jay Lush, and Charles Henderson. Breeding stock Breeding stock is a group of animals used for the purpose of planned breeding. When individuals are looking to breed animals, they look for certain valuable traits in purebred animals, or may intend to use some type of crossbreeding to produce a new type of stock with different, and presumably superior abilities in a given area of endea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mink
Mink are dark-colored, semiaquatic, carnivorous mammals of the genera ''Neogale'' and '' Mustela'' and part of the family Mustelidae, which also includes weasels, otters, and ferrets. There are two extant species referred to as "mink": the American mink and the European mink. The extinct sea mink was related to the American mink but was much larger. The American mink's fur has been highly prized for use in clothing. Their treatment on fur farms has been a focus of animal rights and animal welfare activism. American mink have established populations in Europe (including Great Britain and Denmark) and South America. Some people believe this happened after the animals were released from mink farms by animal rights activists, or otherwise escaped from captivity. In the UK, under the Wildlife and Countryside Act 1981, it is illegal to release mink into the wild. In some countries, any live mink caught in traps must be humanely killed. American mink are believed by some to hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundhog
The groundhog (''Marmota monax''), also known as the woodchuck, is a rodent of the family Sciuridae, belonging to the group of large ground squirrels known as marmots. A lowland creature of North America, it is found through much of the Eastern United States, across Canada and into Alaska. It was given its scientific name as ''Mus monax'' by Carl Linnaeus in 1758, based on a description of the animal by George Edwards (naturalist), George Edwards, published in 1743. The groundhog, being a lowland animal, is exceptional among marmots. Other marmots, such as the yellow-bellied marmot, yellow-bellied and hoary marmots, live in rocky and mountainous areas. Groundhogs are considered one of the most Sociality#Presociality, solitary of Marmot, marmot species. They live in aggregations, and their social organization and long term pair-bonds varies across populations. The groundhog's male and female interactions are usually limited to the mating season and copulation (zoology), copula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamster
Hamsters are rodents (order Rodentia) belonging to the subfamily Cricetinae, which contains 19 species classified in seven genera. They have become established as popular small pets. The best-known species of hamster is the golden or Syrian hamster (''Mesocricetus auratus''), which is the type most commonly kept as a pet. Other hamster species commonly kept as pets are the three species of dwarf hamster, Campbell's dwarf hamster (''Phodopus campbelli''), the winter white dwarf hamster (''Phodopus sungorus'') and the Roborovski hamster (''Phodopus roborovskii''), and the less common Chinese hamster (''Cricetulus griseus''). Hamsters feed primarily on seeds, fruits, vegetation, and occasionally burrowing insects. In the wild, they are crepuscular: they forage during the twilight hours. In captivity, however, they are known to live a conventionally nocturnal lifestyle, waking around sundown to feed and exercise. Physically, they are stout-bodied with distinguishing features ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horse
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature, '' Eohippus'', into the large, single-toed animal of today. Humans began domesticating horses around 4000 BCE in Central Asia, and their domestication is believed to have been widespread by 3000 BCE. Horses in the subspecies ''caballus'' are domesticated, although some domesticated populations live in the wild as feral horses. These feral populations are not true wild horses, which are horses that have never been domesticated. There is an extensive, specialized vocabulary used to describe equine-related concepts, covering everything from anatomy to life stages, size, colors, markings, breeds, locomotion, and behavior. Horses are adapted to run, allowing them to quickly escape predator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ring-tailed Lemur
The ring-tailed lemur (''Lemur catta'') is a medium- to larger-sized strepsirrhine (wet-nosed) primate and the most internationally recognized lemur species, owing to its long, black-and-white, ringed tail. It belongs to Lemuridae, one of five lemur families, and is the only member of the ''Lemur'' genus. Like all lemurs, it is endemic to the island of Madagascar, where it is endangered. Known locally in Malagasy as ' (, spelled ' in French) or ', it ranges from gallery forests to spiny scrub in the southern regions of the island. It is omnivorous, as well as the most adapted to living terrestrially of the extant lemurs. The ring-tailed lemur is highly social, living in groups—known as "troops"—of up to 30 individuals. It is also a female-dominant species, a commonality among lemurs. To keep warm and reaffirm social bonds, groups will huddle together. Mutual grooming is another vital aspect of lemur socialization (as with all primates), reaffirming social and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pineal Gland
The pineal gland (also known as the pineal body or epiphysis cerebri) is a small endocrine gland in the brain of most vertebrates. It produces melatonin, a serotonin-derived hormone, which modulates sleep, sleep patterns following the diurnal cycles. The shape of the gland resembles a pine cone, which gives it its name. The pineal gland is located in the epithalamus, near the center of the brain, between the two cerebral hemisphere, hemispheres, tucked in a groove where the two halves of the thalamus join. It is one of the neuroendocrinology, neuroendocrine Circumventricular organs, secretory circumventricular organs in which capillaries are mostly Vascular permeability, permeable to solutes in the blood. The pineal gland is present in almost all vertebrates, but is absent in Protochordata, protochordates in which there is a simple pineal homologue. The hagfish, archaic vertebrates, lack a pineal gland. In some species of amphibians and reptiles, the gland is linked to a light-s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melatonin
Melatonin, an indoleamine, is a natural compound produced by various organisms, including bacteria and eukaryotes. Its discovery in 1958 by Aaron B. Lerner and colleagues stemmed from the isolation of a substance from the pineal gland of cows that could induce skin lightening in common frogs. This compound was later identified as a hormone secreted in the brain during the night, playing a crucial role in regulating the sleep-wake cycle, also known as the circadian rhythm, in vertebrates. In vertebrates, melatonin's functions extend to Entrainment (chronobiology), synchronizing sleep-wake cycles, encompassing sleep-wake timing and blood pressure regulation, as well as controlling seasonal rhythmicity (circannual cycle), which includes reproduction, fattening, molting, and hibernation. Its effects are mediated through the activation of melatonin receptors and its role as an antioxidant. In plants and bacteria, melatonin primarily serves as a defense mechanism against oxidative ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoperiod
Photoperiod is the change of day length around the seasons. The rotation of the earth around its axis produces 24 hour changes in light (day) and dark (night) cycles on earth. The length of the light and dark in each phase varies across the seasons due to the tilt of the earth around its axis. The photoperiod defines the length of the light, for example a summer day the length of light could be 16 hours while the dark is 8 hours, whereas a winter day the length of day could be 8 hours, whereas the dark is 16 hours. Importantly, the seasons are different in the northern hemisphere than the southern hemisphere. Photoperiodism is the physiological reaction of organisms to the length of light or a dark period. It occurs in plants and animals. Plant photoperiodism can also be defined as the developmental responses of plants to the relative lengths of light and dark periods. They are classified under three groups according to the photoperiods: short-day plants, long-day plants, and day ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
