Misplaced Pages

#874125

47-460: Pentalagus Bunolagus Nesolagus Romerolagus Brachylagus Sylvilagus Oryctolagus Poelagus Caprolagus Pronolagus Lepus † Aztlanolagus † Nuralagus Leporidae ( / l ə ˈ p ɔː r ɪ d iː , - d aɪ / ) is the family of rabbits and hares , containing over 70 species of extant mammals in all. The Latin word Leporidae means "those that resemble lepus " (hare). Together with

94-635: A LH surge to occur, little intromission is required. The pathways in which information reaches the brain and causes GnRH release are not understood well; however, midbrain and brainstem noradrenergic neurones appear to be activated in response to intromission during mating. These neurones then go on to stimulate the mediobasal hypothalamic to release GnRH from the median eminence. Most experiments on GnRH and LH release have been focused on spontaneous ovulators, though there have been studies completed on some induced ovulators (e.g., rabbits, ferrets). From this, it appears that norepinephrine facilitates GnRH release in

141-462: A better reproductive potential for those species that typically have shorter life spans and less encounters resulting in lower mating opportunities throughout their lifetime. Other species may be 'facultatively-induced ovulators' meaning that while they can spontaneously ovulate, the cycle may speed up or slow down depending on the presence of males, females or mating. Some rodents such as squirrels and mole-rats are known induced ovulators. In rats

188-487: A buck can induce ovulation, although there were no data presented in these early reports. Dromedary camels ( Camelus dromedarius ), bactrian camels ( Camelus bactrianus ), llamas ( Lama glama ) and alpacas ( Lama pacos ) are all induced ovulators. Bactrian camels ovulate after insemination into the vagina; it is the seminal plasma, but not the spermatozoa, which induces ovulation. Ovulation occurs in 87% of females after insemination: 66% ovulate within 36 hours and

235-551: A healthy balance of mature and young forests still exists on the southern end of Amami. Restricting logging would also help to keep more forest available for the rabbits to live in by leaving more forest standing, as well as disturbing the surrounding environment more. An end to the building of forest roads used for logging and travel would further protect the Amami rabbit, as they cause population and habitat fragmentation , destroys their prime habitat and allows predators easier access to

282-471: A lesser-known induced ovulator. The koalas require mating in which the presence of ejaculated semen is needed to stimulate the female to produce a LH surge (which would cause ovulation of a follicle). Unlike many other animals, simply being in the presence of a male koala is not enough to induce ovulation itself, nor is vaginal stimulation on its own sufficient to cause induced ovulation to occur. Cats are another widely-known induced ovulator. After mating,

329-512: A number of hormones such as prostaglandin, pfg2a. As well as releasing progesterone by intravaginal devices called CIDRs (Controlled Intravaginal Drug Releas) Domestic cats are often described as induced ovulators. During intromission, the penis probably causes distension of the posterior vagina and induces release of gonadotropin releasing hormone (GnRH) from the hypothalamus via neuroendocrine reflexes. A surge of luteinising hormone (LH) occurs within minutes of mating. With multiple matings,

376-752: A remarkable range of habitats, from desert to tundra , forests , mountains , and swampland . Some rabbits dig burrows for shelter, the exact form of which varies between species. Other rabbits do not dig burrows but use forms, usually under a bush. Hares rarely dig shelters of any kind, instead using forms, and their bodies are more suited to fast running than to burrowing. Leporids are typically polygynandrous , and some have highly developed social systems. Their social hierarchies determine which males mate. Rabbits are induced ovulators (ovulate during mating). Species nesting below ground tend to have lower predation rates and have larger litters. The gestation period in leporids varies from around 28 to 50 days, and

423-458: A variety of carp types, bream and loach are able to be induced to ovulate by using agonists of dopamine . This induction of ovulation from drugs is able to cause a predictable ovulation period and is very beneficial to farming of these species. The natural cycle of spontaneous ovulation occurs in species such as cows . There is a great demand for ovulation to be induced in cattle, as it allows farmers to synchronize their cattle to ovulate at

470-418: Is described as the process in which an oocyte (female germ cell) is released from the follicle . Ovulation is a non-deleterious 'inflammatory response' which is initiated by a luteinizing hormone (LH) surge. The mechanism of ovulation varies between species. In humans the ovulation process occurs around day 14 of the menstrual cycle , this can also be referred to as 'cyclical spontaneous ovulation'. However

517-547: Is generally longer in the hares. This is in part because young hares (called leverets) are born precocial (eyes and ears open, fully furred), while young rabbits (called kits) are born altricial (eyes and ears closed, no fur). Higher latitudes correspond to shorter gestation periods. Leporids can have several litters a year, which can cause their population to expand dramatically in a short time when resources are plentiful. Gestation period and litter size correspond to predation rates as well. The oldest known leporid species date from

SECTION 10

#1732766013875

564-666: Is good, reflecting their primarily nocturnal or crepuscular mode of living. Leporids are all roughly the same shape and fall within a small range of sizes with short tails, ranging in overall length from the 21 cm (8 in) long Tres Marias cottontail to the 76 cm (30 in) long desert hare . Female leporids are almost always larger than males, which is unusual among terrestrial mammals. Both rabbits and hares are almost exclusively herbivorous (although some Lepus species are known to eat carrion), feeding primarily on grasses and herbs, although they also eat leaves, fruit, and seeds of various kinds. Easily digestible food

611-488: Is processed in the gastrointestinal tract and expelled as regular feces. But in order to get nutrients out of hard to digest fiber, leporids ferment fiber in the cecum (in the GI tract) and then expel the contents as cecotropes , which are reingested (cecotrophy). The cecotropes are then absorbed in the small intestine to utilize the nutrients. The dental formula of leporids is: 2.0.3.3 1.0.2.3 = 28. They have adapted to

658-543: Is the process in which the pre-ovulatory LH surge and therefore ovulation is induced by some component of coitus e.g. receipt of genital stimulation. Usually, spontaneous steroid-induced LH surges are not observed in induced ovulator species throughout their reproductive cycles, which indicates that GnRH release is absent or reduced due to lack of positive feedback action from steroid hormones. However, by contradiction, some spontaneously ovulating species can occasionally undergo mating-induced preovulatory LH surges. Species in which

705-443: Is thick, wooly and dark, brown on top and becomes more reddish-brown on the sides. It has heavy, long and very strong claws, being nearly straight on the forefeet and curved on the hindfeet The eyes are also small compared to more common rabbits and hares. The average weight is 2.5–2.8 kg. The ideal habitat for these rabbits is in an area between mature and young forests. They use the dense mature forests as protection and for

752-469: Is thought to be a descendant of Pliopentalagus , known from the Pliocene of China and Eastern to Central Europe. The generic name Pentalagus , as described by Marcus Ward Lyon Jr. , refers to the presence of five molars on each side of the Amami rabbit's teeth, differing from each other extant then-known rabbit genera in that it lacks a third upper molar. The specific name furnessi refers to

799-518: The East African mole rat and the Cape-Dune, Natal, Highvield and blind mole rats are known induced ovulators. These species require mating to stimulate the vagina and cervix, resulting in ovulation in the females. The East African mole rat has been found to have small spines on its penis which are also thought to contribute to this stimulation of induced ovulation. The koala species are

846-572: The Ryukyu rabbit is a dark-furred species of rabbit which is only found on Amami Ōshima and Tokunoshima , two small islands between southern Kyūshū and Okinawa in Japan. Often called a living fossil , the Amami rabbit is a living remnant of ancient rabbits that once lived on the Asian mainland, where they died out, remaining only on the two small Japanese islands where they live today. Pentalagus

893-408: The hypothalamus to the anterior pituitary gland ) to ultimately cause a pre-ovulatory LH surge . Spontaneously ovulating species go through menstrual cycles and are fertile at certain times based on what part of the cycle they are in. Species in which the females are spontaneous ovulators include rats , mice , guinea pigs , horse , pigs , sheep , monkeys , and humans. Induced ovulation

940-545: The pikas , the Leporidae constitute the mammalian order Lagomorpha . Leporidae differ from pikas in that they have short, furry tails and elongated ears and hind legs. The common name "rabbit" usually applies to all genera in the family except Lepus , while members of Lepus (almost half the species) usually are called hares. Like most common names, however, the distinction does not match current taxonomy completely; jackrabbits are members of Lepus , and members of

987-452: The seminal plasma , and not by the spermatozoa . Although the evolution of these two types of ovulation is not well understood, the type of ovulation that would be advantageous in some species can be understood by looking at social groups. Animals that have large, complex social groups benefit from spontaneous ovulation as only the best males get to breed with females. If there are few males suitable for breeding it makes sense to spread out

SECTION 20

#1732766013875

1034-629: The Amami jay. In July 2008, the Amami Rangers for nature conservation obtained a photograph of a feral cat carrying a rabbit corpse (rabbit bones and fur found in cat or dog droppings had already been found), prompting discussions on better ways to control pets. A small area of the Amami Island has the Amami Guntō National Park that further protects the population. Some attempt at habitat restoration has been made, but

1081-426: The Amami rabbit needs a mosaic of mature and young forest in close proximity, and when a young forest is regrown nowhere near a mature forest, this rabbit is not likely to inhabit it. Research and population monitoring also is underway to try to keep the numbers from declining, even if they can not be increased. Suggested conservation work for the future includes habitat restoration and predator population control, as

1128-519: The Amami rabbit primarily feeds on Japanese pampas grass, and during winter, they primarily eat the acorns of the pasania tree. The Amami rabbit also eats the fruits of Balanophora yuwanensis , a parasitic flowering plant, for which they are the main distributors of seed. The Amami rabbit has short feet and hind legs, a somewhat bulky body, and rather large and curved claws used for digging and sometimes climbing. Its ears are significantly smaller compared to those of other hares or rabbits. The pelage

1175-684: The Conservation of Nature and Natural Resources proposed a plan of conservation in 1990. In Amami-Oshima Island, the Amami Wildlife Conservation Center of the Ministry of the Environment was established in 1999. It designated the Amami rabbit as endangered in 2004 for Japan and restarted a mongoose eradication program in 2005. Induced ovulation (animals) Ovulation occurs at the ovary surface and

1222-507: The LH levels in female cats surge, and the time to ovulation can be predicted to occur between 1–2 days later. Wolverines are other known induced ovulators which require physical mating to cause ovulation. Induced ovulation occurs in various carnivoran species, including most felids and several species of mustelids . Many bear species are able to have induced ovulation including the grizzly bear , black bear and polar bear where both

1269-643: The LH surge is greater and lasts longer than when only one mating occurs. There are reports of ovulation without mating in cats. Spontaneous ovulation not only occurs in cats, but occurs with some frequency. It appears that non-copulatory ovulation may be possible in response to a variety of visual, auditory or olfactory cues. It is more appropriate to consider domestic cats to be both an induced and spontaneous ovulator. It has been known since 1905 that domestic rabbits are physically induced ovulators, although they may also ovulate spontaneously. Early reports stated that simply having an oestrous doe in close proximity to

1316-989: The characteristic leporid ankle, thus pushing the divergence of Ochotonidae and Leporidae yet further into the past. The cladogram is from Matthee et al., 2004, based on nuclear and mitochondrial gene analysis. Nesolagus (striped rabbits) Poelagus (Bunyoro rabbit) Pronolagus  (red rock hares) Romerolagus (volcano rabbit) Sylvilagus (cottontails) [REDACTED] Brachylagus  (pygmy rabbit) Caprolagus (hispid hare) Oryctolagus  (European rabbit) [REDACTED] Bunolagus (riverine rabbit) Pentalagus  (Amami rabbit) Lepus (hares) [REDACTED] Family Leporidae ( rabbits and hares ): Predators of rabbits and hares include raccoons , snakes , eagles , canids , cats , mustelids , owls and hawks . Animals that eat roadkill rabbits include vultures and buzzards . Pentalagus The Amami rabbit ( Pentalagus furnessi ), also known as

1363-417: The current habitat for these rabbits for the construction of golf courses and resorts, which is allowed because it will not directly be killing the rabbit, just changing the environment where it dwells, which is legal even under the protection of the special natural monument status. The Amami rabbit also faces huge threats from the invasive predators, being a major cause for the decline in population size. On

1410-404: The females are induced ovulators include cats , rabbits , ferrets , and camels . In 1985, Chen et al. , used Bactrian camels to investigate the factor(s) that induce ovulation during breeding season. They monitored the camel ovaries for ovulation by rectal palpation following insemination of semen samples. Chen et al. , concluded that in this particular camel species ovulation was induced by

1457-906: The genera Pronolagus and Caprolagus sometimes are called hares. Various countries across all continents except Antarctica and Australia have indigenous species of Leporidae. Furthermore, rabbits, most significantly the European rabbit , Oryctolagus cuniculus , also have been introduced to most of Oceania and to many other islands, where they pose serious ecological and commercial threats. Leporids are small to moderately sized mammals, adapted for rapid movement. They have long hind legs, with four toes on each foot, and shorter fore legs, with five toes each. The soles of their feet are hairy, to improve grip while running, and they have strong claws on all of their toes. Leporids also have distinctive, elongated and mobile ears, and they have an excellent sense of hearing. Their eyes are large, and their night vision

Leporidae - Misplaced Pages Continue

1504-424: The hole with soil and plant material by thumping on it with her front paws. Amami rabbits sleep during the day in hidden locations, such as caves. They are also noted for having a call similar to that of a pika . Before 1921, hunting and trapping were another cause of decline in population numbers. In 1921, Japan declared the Amami rabbit a "natural monument" which prevented it from being hunted. Then in 1963, it

1551-414: The island of Amami, the small Indian mongoose ( Urva auropunctata ) was released to control the population of a local venomous snake, and its numbers have increased dramatically. This mongoose, along with feral cats and dogs, are outpreying the Amami rabbit. Feral cats and small Indian Mongooses proved to be a threat to not only Amami rabbits but several other endangered endemic species in the area such as

1598-666: The late Eocene , by which time the family was already present in both North America and Asia. Over the course of their evolution, this group has become increasingly adapted to lives of fast running and leaping. For example, Palaeolagus , an extinct rabbit from the Oligocene of North America, had shorter hind legs than modern forms (indicating it ran rather than hopped) though it was in most other respects quite rabbit-like. Two as yet unnamed fossil finds—dated ~48 Ma (48 million yr) ago (from China ) and ~53 Ma (53 million yr) ago ( India )—while primitive, display

1645-470: The middle of forests where a majority of the rabbit population exists. Controlling the populations of mongooses, feral dogs, and feral cats is another approach that could help bolster the rabbit population. Eradication of the mongooses and feral cats and dogs is needed, as well as better control of pets by local island residents. The Lagomorph Specialist Group of the International Union for

1692-421: The monthly menstruation process is typically linked to humans and primates , all other animal species ovulate by various other mechanisms. Spontaneous ovulation is the ovulatory process in which the maturing ovarian follicles secrete ovarian steroids to generate pulsatile GnRH (the neuropeptide which controls all vertebrate reproductive function) release into the median eminence (the area which connects

1739-555: The number of rabbits is estimated at 2000–4800 left on Amami Island and 120–300 left on Tokuno Island. This species is a nocturnal forest-dweller that reproduces once in late March–May and once in September–December, having one or two young each time. During the day, the mother digs a hole in the ground, for her young to hide in. At night, she opens the entrance to the hole, while watching for predators (such as venomous snakes ), and then nurses her young, after which she closes

1786-451: The original discoverer of the Amami rabbit, William Henry Furness III . The Amami rabbit feeds on over 29 species of plants, which incorporates 17 species of shrubs and 12 species of herbaceous plants , consuming mostly the sprouts, young shoots and acorns . It also eats nuts and cambium of a wide variety of plant species. It is observed that the Amami rabbit also feeds on the bark of stems and twigs of shrub plants. During summer,

1833-462: The presence of pampas grass , in the summer, and acorns , in the winter, for their diets. They also use the high density of perennial grasses and herbaceous ground cover in the young forests for their diets during different times of the year. Therefore, the best habitat for them to live in is where they have easy access to both young and mature forests with no obstructions between the two forest types. Using fecal pellet counts and resident surveys,

1880-432: The presence of a male and mating itself are requirements for induced ovulation. However, there are some suggestions that mating is not as strict a requirement for ovulation in bears. Japanese black bears are induced ovulators. It was observed that most females kept separate from males did not ovulate, whereas females kept in areas with male bears did. Mating between the bears caused elevated progesterone levels, and this

1927-450: The rabbit and ferret and the locus coereuleus which is the part of the brain involved in conveying genital-somatosensory information to the GnRH neurones. Other substances that have similar effects include neuropeptide Y . Many species have been found to be induced ovulators and the reasons for this are not always clear. However, one possible reason is that induced ovulation could provide

Leporidae - Misplaced Pages Continue

1974-462: The release of the egg. Ovulation is triggered in induced ovulators by an LH surge from the anterior pituitary that is induced during mating. Animals this has been recorded in include rabbits, voles, ferrets and camels. In some species such as the ferret, the duration of intromission has no effect on the LH surge, whereas in other species such as the cat these are related and higher levels of LH were produced by mating multiple times. In many species, for

2021-424: The rest by 48 hours (the same as natural mating). The least amount of semen required to elicit ovulation is about 1.0 ml. In alpaca, follicles ovulate approximately 26 hours after coital stimulation. Mounting accompanied by intromission is necessary to provide adequate stimulation for LH release and subsequent ovulation. Deposition of semen, which contains ovulation-inducing factor (OIF), has been shown to increase

2068-442: The same time, helping improve the efficiency of dairy farming. Induced ovulation can be utilized during the warmer seasons to increase plasma progesterone and improve the fertility of the cattle. However, ovulation can only be induced in cows with mature follicles and merely initiates lutenization, it does not reduce the time for ovulation. There are a number of methods that are used to induce ovulation in cattle such as: introducing

2115-435: The times at which females are fertile, therefore increasing the proportion in which conception occurs. This does not explain the evolution of ovulation in all species however, for example some species appear to show estrus synchronisation. In spontaneous ovulators, estrogen and progesterone secreted by the follicles as they grow and mature affects the release of GnRH, and therefore causes an LH surge. The LH surge then causes

2162-498: Was changed to a "special natural monument" which prevented it from being trapped as well. Habitat destruction , such as forest clearing for commercial logging, agriculture space, and residential areas, is the most detrimental activity on the distribution of these rabbits. Since they prefer a habitat of both mature and young forests, they do not thrive in only mature forests untouched by destruction, yet they do not thrive in newly growing forests alone, either. There are plans to remove

2209-455: Was seen by increased progesterone levels measured in the bears in the months that followed the mating seasons. In Japanese black bears, the presence of a male was enough to cause a notable rise in progesterone levels even without mating. This could suggest that pheromonal / chemosensory factors could also contribute to induced ovulation in some species. Induced ovulation is able to occur in some fish species. In China freshwater fish including

#874125