114-524: Neotoma albigula Neotoma angustapalata Neotoma chrysomelas Neotoma cinerea Neotoma devia † Neotoma findleyi Neotoma floridana Neotoma fuscipes Neotoma goldmani Neotoma insularis Neotoma lepida Neotoma leucodon Neotoma macrotis Neotoma magister Neotoma melanura Neotoma mexicana Neotoma micropus Neotoma nelsoni Neotoma palatina Neotoma phenax Neotoma stephensi A pack rat or packrat , also called
228-407: A bolus before being transported down the esophagus through peristalsis . The sublingual region underneath the front of the tongue is a location where the oral mucosa is very thin, and underlain by a plexus of veins. This is an ideal location for introducing certain medications to the body. The sublingual route takes advantage of the highly vascular quality of the oral cavity, and allows for
342-816: A woodrat or trade rat , are any species in the North and Central American rodent genus Neotoma . Pack rats have a rat-like appearance, with long tails, large ears, and large, black eyes. Pack rats are noticeably larger than deer mice , harvest mice , and grasshopper mice , and are usually somewhat larger than cotton rats . Neotoma includes three subgenera, Daggers (†) mark extinct species: Packrats typically have wide eyes accompanied with long whiskers. They have large ears that extend outwards. In terms of size, they resemble Norway rats. They grow to be approximately 30 cm long, with their tails making up about 50% of their size. Long-haired pack rats specifically have tails that are adequately furry and are physically compared to
456-436: A 98- to 164-foot (30–50 m) radius of their dens. Digestion Digestion is the breakdown of large insoluble food compounds into small water-soluble components so that they can be absorbed into the blood plasma . In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream . Digestion is a form of catabolism that is often divided into two processes based on how food
570-424: A blood and nerve supply which enables proprioception. This is the ability of sensation when chewing, for example if we were to bite into something too hard for our teeth, such as a chipped plate mixed in food, our teeth send a message to our brain and we realise that it cannot be chewed, so we stop trying. The shapes, sizes and numbers of types of animals' teeth are related to their diets. For example, herbivores have
684-587: A bushy, almost squirrel-like tail. Bushy-tailed woodrats Neotoma cinerea occupy a range of habitats from boreal woodlands to deserts. They are cliff-dwellers and are often found on isolated, high-elevation exposed boulder areas under a variety of temperature and moisture conditions. They require adequate shelter among the rocks, though they are occasionally found inhabiting abandoned buildings as well. Pack rats are nest builders. They use plant material such as twigs, sticks, and other available debris. They are particularly fond of shiny objects. A peculiar characteristic
798-800: A complete list of foods eaten by white-throated woodrats in the Santa Rita Experimental Range, see Vorhies and Taylor. In the southern Great Basin, Navajo yucca ( Y. baileyi ) is an important food for the white-throated woodrat. White-throated woodrats require large amounts of water obtained through various xerophytic plants, especially cacti. In Organ Pipe National Monument, white-throated woodrats relied heavily on teddybear cholla, buckhorn cholla ( Cylindropuntia acanthocarpa ), jumping cholla, and goatnut ( Simmondsia spp.) for water. In Coconino County, white-throated woodrats obtained water from evergreen species ( Ephedra spp., Yucca spp., and Juniperus spp.), which maintained
912-410: A complex digestive system as do, for example, ruminants. Instead they extract more nutrition from grass by giving their food a second pass through the gut . Soft faecal pellets of partially digested food are excreted and generally consumed immediately. They also produce normal droppings, which are not eaten. Young elephants, pandas, koalas, and hippos eat the faeces of their mother, probably to obtain
1026-428: A crop or enlarged esophagus . Herbivores have evolved cecums (or an abomasum in the case of ruminants ). Ruminants have a fore-stomach with four chambers. These are the rumen , reticulum , omasum , and abomasum. In the first two chambers, the rumen and the reticulum, the food is mixed with saliva and separates into layers of solid and liquid material. Solids clump together to form the cud (or bolus ). The cud
1140-408: A general response to stress conditions, the process of loading cargo proteins seems to be selective. The gastrovascular cavity functions as a stomach in both digestion and the distribution of nutrients to all parts of the body. Extracellular digestion takes place within this central cavity, which is lined with the gastrodermis, the internal layer of epithelium . This cavity has only one opening to
1254-411: A hand to grab pieces of dead grass, leaves, and weeds, with bits of soil to help chew. The lips break the food down into smaller pieces. In the pharynx, the food is lubricated by mucus secretions for easier passage. The esophagus adds calcium carbonate to neutralize the acids formed by food matter decay. Temporary storage occurs in the crop where food and calcium carbonate are mixed. The powerful muscles of
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#17327905050101368-414: A harsh summer climate, ease of burrowing in loose sand, scarcity of building materials, or adequate overhead protection by honey mesquite. River banks were 6 to 15 feet (2–5 m) high, and burrows were excavated at various heights from the bottom. Hole diameter was 3.5 to 7 inches (8.9–18 cm). White-throated woodrats also dwelled in burrows with as many as 8 openings, covered with a few small twigs, at
1482-466: A high year-round water content. The white-throated woodrat diet varies seasonally. In Coconino County, white-throated woodrats ate a variety of plants, including deciduous shrubs, during warm, wet months when plant moisture was high. During cool, dry months, their diet was restricted largely to evergreen plants. Regardless of season, white-throated woodrats preferred to eat evergreen species. At Carrizo Creek, honey mesquite leaves, flowers, and fruits were
1596-465: A higher percentage of forbs and rocks than a mesquite bosque. The active riparian channel and floodplain was dominated by desert willow, velvet ash (Fraxinus velutina), Arizona sycamore (Platanus wrightii), and velvet mesquite. The mesquite bosque was dominated by velvet mesquite, catclaw acacia, and broom snakeweed. In pinyon-juniper woodlands in Grant County, New Mexico , total overstory density
1710-1050: A large geographic range, and its body size is closely correlated with climate. Average males range in size from 310 to 470 mm (12 to 19 in), with the average being 379 mm (14.9 in), and average females range from 272 to 410 mm (10.7 to 16.1 in), with the average being 356 mm (14.0 in). Reproductive habits of rodents are variable in the wild. Offspring are born naked and helpless and must be cared for in nests called middens. Some female pack rats have been known to deliver up to five litters per year with each litter having as many as five young. The offspring may open their eyes between 10 and 12 days after being born and are usually weaned between 14 and 42 days. After around 60 days, most become sexually mature. Populations may cycle approximately every 8 years due to variation in reproduction and juvenile survival. Female annual survival rates vary by age from 0.42 for juveniles to 0.71 for 1–2 year olds, and very few females (less than 5%) live beyond 3 years of age. A pack rat midden
1824-478: A material known as amberat, which under some conditions can cement the midden together, and can encase plant fragments, pellets and other debris in an amber -like matrix . The resilience of the middens is aided by three factors. The crystallized urine dramatically slows the decay of the materials in the midden; the dry climate of the American Southwest further slows the decay; and middens protected from
1938-519: A minimum spacing of 20.0 feet (6.1 m) and left in place. The table below shows total numbers of woodrats on 4 plots: White-throated woodrat density increased in a pinyon-juniper woodland in Grant County, New Mexico, where trees were uprooted and piled to improve livestock grazing. The felled trees provided white-throated woodrats with cover and building materials. White-throated woodrats must rely on self-constructed, ground-level shelter to lower
2052-818: A nearby dry water development. White-throated woodrats also occupied a human constructed desert riparian habitat at No Name Lake on the Colorado River Indian Reservation on the Arizona side of the Colorado River . The area was cleared of nonnative tamarisk ( Tamarix spp.) and 80% of the area was planted with native Fremont cottonwood and honey mesquite. Other vegetation included Goodding's willow Salix gooddingii , blue paloverde ( Parkinsonia florida ), big saltbush ( Atriplex lentiformis ), and California fan palm ( Washingtonia filifera ). Habitat with abundant coarse woody debris
2166-416: A nuisance. Bushy-tailed woodrats feed primarily on green vegetation, twigs, and shoots. Mexican woodrats eat seeds, fruits, acorns, and cactus. The pack rat microbiome has symbiotic roles in digestion , recycling endogenous nitrogen , and the detoxification of dietary toxins. The bacterial composition of the pack rat’s gut microbiome is affected by what it eats, and by association, the geography of where
2280-483: A number of molars which are used to grind plant matter, which is difficult to digest. Carnivores have canine teeth which are used to kill and tear meat. A crop , or croup, is a thin-walled expanded portion of the alimentary tract used for the storage of food prior to digestion. In some birds it is an expanded, muscular pouch near the gullet or throat. In adult doves and pigeons, the crop can produce crop milk to feed newly hatched birds. Certain insects may have
2394-667: A pinyon-juniper woodland in the Gila National Forest, New Mexico, white-throated woodrats responded favorably to mechanical treatments that increased the amount of coarse woody debris. Of 4 treatments (untreated; bulldozed/piled/burned; bulldozed; and thinned), white-throated woodrats were most abundant on bulldozed plots and thinned plots, where slash accumulations were 2.5 to 3 times greater than on other plots. On bulldozed plots, Colorado pinyon, one-seed juniper, and alligator juniper trees were pushed over and left in place. On thinned plots, Colorado pinyon and juniper were cut to
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#17327905050102508-589: A site for fermentation of indigestible matter by gut bacteria and for resorption of water from digests before excretion. In mammals , preparation for digestion begins with the cephalic phase in which saliva is produced in the mouth and digestive enzymes are produced in the stomach . Mechanical and chemical digestion begin in the mouth where food is chewed , and mixed with saliva to begin enzymatic processing of starches . The stomach continues to break food down mechanically and chemically through churning and mixing with both acids and enzymes. Absorption occurs in
2622-407: A slimy layer that acts as a shield against the damaging effects of chemicals like concentrated hydrochloric acid while also aiding lubrication. Hydrochloric acid provides acidic pH for pepsin. At the same time protein digestion is occurring, mechanical mixing occurs by peristalsis, which is waves of muscular contractions that move along the stomach wall. This allows the mass of food to further mix with
2736-560: A system of runways and chambers, including the white-throated woodrat's nest. The nest averages 8 inches (20 cm) in diameter and is composed of soft, fine material including grass, shredded prickly-pear fibers, or juniper bark. White-throated woodrats use locally available building materials to construct houses. In wooded areas, white-throated woodrats use sticks and other debris, and in deserts, parts of cacti, catclaw acacia, mesquite, and yucca are typically used. Cactus parts are preferred building materials; preference for cacti
2850-511: A variety of plant communities from sea level to 9,200 feet (2,800 m) but is most common in Sonoran and Chihuahuan desert grassland and desert shrub habitats. The white-throated woodrat is generally associated with creosotebush, mesquite, cacti (particularly prickly-pear and cholla ( Cylindropuntia spp.)), catclaw acacia, and paloverde. These plants provide cover and succulent plant food (>50% water by weight) (see section "Food habits"),
2964-425: A variety of techniques to analyze the plant and animal material in pack rat middens describe paleo-communities and infer paleo-climate. For example, the plant species present in middens, and the carbon isotope ratios on material in middens have been widely studied. The analysis of middens was key in understanding the biota around Pueblo Bonito , thus helping to explain its history. One form of midden analysis examined
3078-426: Is a vacuole formed around a particle absorbed by phagocytosis . The vacuole is formed by the fusion of the cell membrane around the particle. A phagosome is a cellular compartment in which pathogenic microorganisms can be killed and digested. Phagosomes fuse with lysosomes in their maturation process, forming phagolysosomes . In humans, Entamoeba histolytica can phagocytose red blood cells . To aid in
3192-410: Is a debris pile constructed by a woodrat. A midden may preserve the materials incorporated into it for up to 50,000 years. These midden piles may be analyzed to reconstruct their original environment, and comparisons between middens allow a record of vegetative and climate change to be built. Examinations and comparisons of pack rat middens have largely supplanted pollen records as a method of study in
3306-435: Is also triggered by acetylcholine and histamine . The intestinal phase has two parts, the excitatory and the inhibitory. Partially digested food fills the duodenum . This triggers intestinal gastrin to be released. Enterogastric reflex inhibits vagal nuclei, activating sympathetic fibers causing the pyloric sphincter to tighten to prevent more food from entering, and inhibits local reflexes. Protein digestion occurs in
3420-408: Is broken down: mechanical and chemical digestion. The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes . Mechanical digestion takes place in the mouth through mastication and in the small intestine through segmentation contractions . In chemical digestion , enzymes break down food into
3534-415: Is finally moved into the small intestine, where the digestion and absorption of nutrients occurs. Microbes produced in the reticulo-rumen are also digested in the small intestine. Regurgitation has been mentioned above under abomasum and crop, referring to crop milk, a secretion from the lining of the crop of pigeons and doves with which the parents feed their young by regurgitation. Many sharks have
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3648-640: Is found from central Mexico north to Utah and Colorado in the United States. It is primarily a western species in the United States, extending from central Texas west to southeastern California . Populations east of the Rio Grande in New Mexico and Trans-Pecos Texas, previously considered to be variants of the white-throated woodrat, have since 1988 been assigned to the white-toothed woodrat ( Neotoma leucodon ). The animal lives mostly in
3762-564: Is preferred by white-throated woodrats for cover (see Cover). In pinyon-juniper woodlands at the Piñon Canyon Maneuver site near Trinidad, Colorado , white-throated woodrats were captured most often in areas with coarse woody debris. In an actively flooded riparian channel and floodplain at Montezuma Castle National Monument, white-throated woodrat occurrence was significantly (P<0.05) greater in areas containing coarse woody debris than areas without coarse woody debris. In
3876-422: Is skeletal muscle on the floor of the mouth of most vertebrates, that manipulates food for chewing ( mastication ) and swallowing (deglutition). It is sensitive and kept moist by saliva . The underside of the tongue is covered with a smooth mucous membrane . The tongue also has a touch sense for locating and positioning food particles that require further chewing. The tongue is used to roll food particles into
3990-590: Is slightly acidic (about 5.6 ~ 6.9). Some vitamins, such as biotin and vitamin K (K 2 MK7) produced by bacteria in the colon are also absorbed into the blood in the colon. Absorption of water, simple sugar and alcohol also takes place in stomach. Waste material ( feces ) is eliminated from the rectum during defecation . Digestive systems take many forms. There is a fundamental distinction between internal and external digestion. External digestion developed earlier in evolutionary history, and most fungi still rely on it. In this process, enzymes are secreted into
4104-596: Is so strong that white-throated woodrat houses may not contain a proportionally representative sample of the surrounding plant community. Other building materials used by white-throated woodrats across their range include feces, bones, and human objects. Of 100 white-throated woodrat houses found on the Santa Rita Experimental Range, 75 different items were used for construction. The most commonly used building materials included mesquite, catclaw acacia, paloverde, desert ironwood (Olneya tesota), and creosotebush twigs; cholla joints and fruits; portions of prickly-pear where it
4218-400: Is that if they find something they want, they will drop what they are currently carrying—for example, a piece of cactus—and "trade" it for the new item. They can also be quite vocal and boisterous. Entering and inhabiting human spaces like attics or car engines, stealing their treasures from humans, damaging electrical wiring, and creating general noisy havoc. This can easily cause them to become
4332-607: Is the prototypic system. In the nitrogen-fixing Rhizobia , conjugative elements naturally engage in inter- kingdom conjugation. Such elements as the Agrobacterium Ti or Ri plasmids contain elements that can transfer to plant cells. Transferred genes enter the plant cell nucleus and effectively transform the plant cells into factories for the production of opines , which the bacteria use as carbon and energy sources. Infected plant cells form crown gall or root tumors . The Ti and Ri plasmids are thus endosymbionts of
4446-439: Is then regurgitated, chewed slowly to completely mix it with saliva and to break down the particle size. Fibre, especially cellulose and hemi-cellulose , is primarily broken down into the volatile fatty acids , acetic acid , propionic acid and butyric acid in these chambers (the reticulo-rumen) by microbes: ( bacteria , protozoa , and fungi). In the omasum, water and many of the inorganic mineral elements are absorbed into
4560-1037: The Illinoian Stage of the Pleistocene . This is consistent with the oldest known fossils from Slaton, Texas . This rodent is a common fossil in Southwestern cave faunas, with over 20 fossil localities of Pleistocene age known from New Mexico alone. The ranges of the white-throated woodrat and its subspecies are from the southeastern corners of Nevada and California across southern Utah and all of Arizona to southwestern Colorado, across west Texas and south to central Mexico. In general, white-throated woodrats occupy desert grasslands , semiarid shrublands , saguaro ( Carnegiea gigantea ) cactus communities, pinyon-juniper ( Pinus-Juniperus spp.) woodlands, interior ponderosa pine ( P. ponderosa var. scopulorum ) forests, and Madrean evergreen woodland ( Pinus spp.- Quercus spp.). The white-throated woodrat occupies
4674-649: The Sonoran Desert , and in the forest and rocky habitats of the western United States and western Canada. Each species of pack rat is generally restricted to a given type of habitat within its range. Pack rats live anywhere from low, hot, dry deserts to cold, rocky slopes above timberline. Pack rats build complex houses or dens made of twigs, cactus joints, and other materials. These contain several nest chambers, food caches, and debris piles. Dens are often built in small caves or rocky crevices, but when close by human habitations, woodrats will opportunistically move into
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4788-403: The cephalic phase , gastric phase , and intestinal phase . The cephalic phase occurs at the sight, thought and smell of food, which stimulate the cerebral cortex . Taste and smell stimuli are sent to the hypothalamus and medulla oblongata . After this it is routed through the vagus nerve and release of acetylcholine. Gastric secretion at this phase rises to 40% of maximum rate. Acidity in
4902-402: The duodenum where it mixes with digestive enzymes from the pancreas and bile juice from the liver and then passes through the small intestine, in which digestion continues. When the chyme is fully digested, it is absorbed into the blood. 95% of nutrient absorption occurs in the small intestine. Water and minerals are reabsorbed back into the blood in the colon (large intestine) where the pH
5016-405: The esophagus and into the stomach by the action of peristalsis . Gastric juice in the stomach starts protein digestion . Gastric juice mainly contains hydrochloric acid and pepsin . In infants and toddlers , gastric juice also contains rennin to digest milk proteins. As the first two chemicals may damage the stomach wall, mucus and bicarbonates are secreted by the stomach. They provide
5130-488: The 2 most critical habitat requirements for white-throated woodrat. White-throated woodrats prefer habitat with low tree canopy cover, high shrub and rock cover, and coarse woody debris . When available, natural and human constructed riparian habitat may be used by white-throated woodrats. In several studies in Arizona, white-throated woodrats preferred low tree cover and high shrub, rock, and litter cover. In ponderosa pine - Gambel oak habitat in
5244-504: The Cabeza Prieta National Wildlife Refuge in southwestern Arizona, white-throated woodrats were trapped most often in velvet Mesquite Bosque thickets that grew closest to a human constructed water development. White-throated woodrats were trapped least often in habitat dominated by creosotebush and furthest away (distance not given) from the water development. No white-throated woodrats were trapped at
5358-482: The Coconino National Forest, Arizona, was 47,760 ft (4,437 m ). White-throated woodrat density may be governed by the number of suitable plants available for shelter, food, and water. In Joshua Tree National Monument, there was a significant (P<0.001) positive relationship between white-throated woodrat density and teddybear cholla density, which provided shelter, food, and water. In
5472-603: The Coconino National Forest, all white-throated woodrats were captured within 210 feet (64 m) of rocky habitat. In ponderosa pine-Gambel oak habitat in the Hualapai Mountains, white-throated woodrat presence was positively associated with high (3% to 19%) rock cover. The white-throated woodrat is well-adapted to xeric habitats, but may also be found in riparian areas . They may utilize both natural and human-constructed areas when available. At Montezuma Castle National Monument, white-throated woodrat abundance
5586-632: The Hualapai Mountains in Arizona, white-throated woodrat presence was negatively associated with high tree cover and high herbaceous cover and positively associated with high shrub and rock cover. On plots where white-throated woodrats were trapped, mean tree canopy cover ranged from 30% to 57%, mean herbaceous cover ranged from 2% to 10%, mean shrub cover ranged from 5% to 19%, and mean rock cover ranged from 3% to 14%. In desert riparian floodplain habitat at Montezuma Castle National Monument, Arizona, white-throated woodrats were more abundant in an active riparian channel and floodplain that had lower tree cover and
5700-541: The Lower Sonoran desert of Arizona, white-throated woodrats favored some plants because of their structural and food values and favored other plants due to their availability. When available, cholla was used most often for building material due to its structural and food values. Mesquite sticks were used frequently. Although mesquite was seldom used for food, mesquite sticks were abundant at the base of plants so they were readily available. White bursage (Ambrosia dumosa)
5814-701: The Lower Sonoran zone of Arizona and New Mexico, white-throated woodrats commonly used the bases of catclaw acacia for shelter. White-throated woodrats selected multiple-stemmed plants over single-stemmed plants and a dense, low canopy over a tall, thin canopy in habitat dominated by triangle bursage in Organ Pipe Cactus National Monument in Arizona and New Mexico . White-throated woodrats selected house sites in reverse order of plant abundance: yellow paloverde 18.1 plants/ha, 6 houses; desert ironwood, 7.6 plants/ha, 14 houses; and organ pipe cactus, 5.0 plants/ha, 21 houses. Yellow paloverde
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#17327905050105928-410: The Lower Sonoran zone of southern Arizona (Santa Rita Experimental Range), cacti and mesquite were the primary foods eaten. When offered a choice between cacti with spines and cacti without, white-throated woodrats preferred those with spines, possibly because spines indicate cacti with more protein and less fibre. They also placed the spines around their nests, acting as a defence against predators. For
6042-513: The Mesilla Valley of southern New Mexico, white-throated woodrat density was more dependent on plants that provided sufficient water and food than on plants that provided shelter. White-throated woodrats are opportunistic and primarily herbivorous [31]. Their diet consists of seeds, fruits, green portions of plants, flowers, small amounts of grass, and occasionally beetles (Coleoptera), ants (Hymenoptera), and reptiles. Some of
6156-480: The Upper and Lower Sonoran life zones , occurring from pinyon-juniper woodland in higher country to desert habitats at lower elevations. As with other species of woodrats, the white-throated woodrat constructs middens of a variety of materials such as sticks, cactus parts, and miscellaneous debris. An above-ground chamber within the midden contains a nest lined with grasses and kept free of feces. In non-rocky areas,
6270-420: The ability to turn their stomachs inside out and evert it out of their mouths in order to get rid of unwanted contents (perhaps developed as a way to reduce exposure to toxins). Other animals, such as rabbits and rodents , practise coprophagia behaviours – eating specialised faeces in order to re-digest food, especially in the case of roughage. Capybara, rabbits, hamsters and other related species do not have
6384-434: The absorption of nutrients by increasing the surface area of the intestine. Bile helps in emulsification of fats and also activates lipases. In the large intestine, the passage of food is slower to enable fermentation by the gut flora to take place. Here, water is absorbed and waste material stored as feces to be removed by defecation via the anal canal and anus . Different phases of digestion take place including:
6498-573: The active riparian channel and floodplain, body weights of male white-throated woodrat were significantly (P<0.05) higher in the mesquite bosque, suggesting that it was "higher quality" habitat. Although preferred habitat differed between male and female white-throated woodrats on the Santa Rita Experimental Range, Arizona, both genders showed some preference for riparian woodland typified by Arizona white oak and netleaf hackberry: Construction of water developments in xeric habitat in Arizona may provide habitat and water for white-throated woodrats. On
6612-518: The animal is from. However, while the bacterial composition of the pack rat microbiome is influenced by diet and geography, it is the animals’ genetics that has the most influential role on bacterial composition. Adult bushy-tailed woodrat males usually weigh 300–600 g (11–21 oz), with an average of 405 g (14.3 oz), and adult females usually weigh 250–350 g (8.8–12.3 oz), with an average of 270 g (9.5 oz). These ranges are relatively large because this species occupies
6726-436: The attics and walls of houses. Some Neotoma species, such as the white-throated woodrat ( N. albigula ), use the bases of prickly pear or cholla cactus as the sites for their homes, using the cactus' spines for protection from predators. Others, like the desert woodrat ( N. lepida ) will build dens around the base of a yucca or cactus, such as jumping and teddy-bear chollas . The largest species, Neotoma cinerea, has
6840-419: The average ambient air temperature in the region in which the vertebrate lives, so organisms in warmer regions are typically smaller than members of the same species in colder regions. [REDACTED] [REDACTED] [REDACTED] [REDACTED] Neotoma albigula Neotoma albigula varia The white-throated woodrat ( Neotoma albigula ) is a species of rodent in the family Cricetidae . It
6954-412: The bacteria required to properly digest vegetation. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to get any nutritional value from many plant components. An earthworm 's digestive system consists of a mouth, pharynx , esophagus , crop, gizzard , and intestine . The mouth is surrounded by strong lips, which act like
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#17327905050107068-404: The bacteria, which are in turn endosymbionts (or parasites) of the infected plant. The Ti and Ri plasmids are themselves conjugative. Ti and Ri transfer between bacteria uses an independent system (the tra , or transfer, operon) from that for inter-kingdom transfer (the vir , or virulence , operon). Such transfer creates virulent strains from previously avirulent Agrobacteria . In addition to
7182-565: The bacterial cytoplasm into the cytoplasm of its host's cells rather than be secreted into the extracellular medium. The conjugation machinery of some bacteria (and archaeal flagella) is capable of transporting both DNA and proteins. It was discovered in Agrobacterium tumefaciens , which uses this system to introduce the Ti plasmid and proteins into the host, which develops the crown gall (tumor). The VirB complex of Agrobacterium tumefaciens
7296-578: The base of live and dead fallen juniper trees in pinyon-juniper woodlands in Arizona, New Mexico, Utah, and Texas. The base of pinyons are occasionally used. Mesquite is often favored by white-throated woodrats for shelter in habitat dominated by mesquite in New Mexico, Arizona, California, and Texas. In habitat dominated by mesquite and creosote bush in San Diego County, California , all white-throated woodrat houses were located at
7410-449: The base of trees, shrubs, and cacti or in piles of coarse woody debris. White-throated woodrats prefer to construct houses at the bases of plants that provide both adequate shelter and food. Houses are constructed of various materials and are typically 3 to 10 feet (1–3 m) in diameter and up to 3 feet tall. Dens function as houses but are located in rock crevices, rock fissures, and under boulder piles. Houses and dens enclose
7524-932: The base of yucca for shelter sites. On the Jornada Experiment Range in New Mexico, and the Black Gap Wildlife Management Refuge in Trans-Pecos Texas, white-throated woodrats built houses at the bases and fallen trunks of yucca. Soaptree yucca was used by white-throated woodrats in the lower Sonoran zone of the Lordsburg Plains in New Mexico and the San Simon Valley in Arizona. Cholla and prickly-pear are often used by white-throated woodrats for cover because they provide excellent protection from predators, as well as food and water. One of
7638-654: The bases of honey mesquite . Twenty to 26-foot tall (6–8 m) honey mesquite were preferred over 3 to 10 foot (1–3 m) tall honey mesquite, probably because they provided more shelter and abundant, accessible food. An exception in habitat dominated by mesquite occurred on the Santa Cruz river bottom near Tucson, Arizona, where white-throated woodrat houses were also built under netleaf hackberry, American black elderberry ( Sambucus nigra ), skunkbush sumac ( Rhus trilobata ), bear grass ( Nolina spp.), or saguaro . In habitats where yucca are abundant white-throated woodrats use
7752-610: The bases of honey mesquite. In a similar habitat type in the Mesilla Valley of New Mexico, white-throated woodrats denned in sand dunes created by banner-tailed kangaroo rats ( D. spectabilis ) around honey mesquite. The white-throated woodrat is a small rodent measuring an average of 12.9 inches (32.8 cm) and weighing an average of 188 g for females and 224 g for males. With the exception of lactating females, white-throated woodrats are solitary and occupy separate houses. They are primarily nocturnal and are active year-round. According to Brown and Zeng, maximum longevity for
7866-425: The bases of shrub-trees, shrubs, or cacti. When available, rocks are preferred by white-throated woodrats for shelter because they provide more protection from variations in ambient temperature than the base of plants. Although any tree, shrub, or cactus may be used by white-throated woodrats for shelter sites, the most commonly used plants are discussed below. White-throated woodrats construct houses at
7980-849: The bases of vertical cliffs. In habitat dominated by brittle bush in Saguaro National Monument, all 103 white-throated woodrat dens were located within jumbles of rocks or under boulders. Ninety-one dens were located under boulders >7 feet (2 m) in diameter, and 12 dens were located under boulders <7 feet in diameter. White-throated woodrats occasionally use river banks, subterranean areas, or caves for shelter. In habitat dominated by honey mesquite and creosotebush at Carrizo Creek in San Diego County, white-throated woodrats sought cover either in river banks or burrows that were probably excavated by kangaroo rats ( Dipodomys spp.). Lack of stick houses may have been due to
8094-411: The blood stream. The abomasum is the fourth and final stomach compartment in ruminants. It is a close equivalent of a monogastric stomach (e.g., those in humans or pigs), and digesta is processed here in much the same way. It serves primarily as a site for acid hydrolysis of microbial and dietary protein, preparing these protein sources for further digestion and absorption in the small intestine. Digesta
8208-464: The body. In most vertebrates , digestion is a multistage process in the digestive system, starting from ingestion of raw materials, most often other organisms. Ingestion usually involves some type of mechanical and chemical processing. Digestion is separated into four steps: Underlying the process is muscle movement throughout the system through swallowing and peristalsis . Each step in digestion requires energy, and thus imposes an "overhead charge" on
8322-517: The den usually is several feet in diameter and most commonly built around the base of a shrub that gives additional cover. In areas of rocky outcrops, crevices often are utilized, with sticks and other materials preventing free access to the nesting chamber. Molecular data suggest that this species separated from other species of the Neotoma floridana group ( Neotoma floridana , Neotoma micropus , Neotoma leucodon ) about 155,000 years ago during
8436-408: The digestion of their food, animals evolved organs such as beaks, tongues , radulae , teeth, crops, gizzards, and others. Birds have bony beaks that are specialised according to the bird's ecological niche . For example, macaws primarily eat seeds, nuts, and fruit, using their beaks to open even the toughest seed. First they scratch a thin line with the sharp point of the beak, then they shear
8550-414: The digestive enzymes. Pepsin breaks down proteins into peptides or proteoses , which is further broken down into dipeptides and amino acids by enzymes in the small intestine. Studies suggest that increasing the number of chews per bite increases relevant gut hormones and may decrease self-reported hunger and food intake. When the pyloric sphincter valve opens, partially digested food ( chyme ) enters
8664-489: The elements under rock overhangs or in caves survive longer. Zoologists examine the remains of animals in middens to get a sense of the fauna in the neighborhood of the midden, while paleobotanists can reconstruct the vegetation that grew nearby. Middens are considered reliable "time capsules" of natural life, centuries and millennia after they occurred. Woodrat middens are composed of many things, including plants, macrofossils, and fecal pellets. Paleo-ecologists have used
8778-517: The energetic costs of thermoregulation in extreme environments. White-throated woodrats typically use 2 types of shelter: houses, constructed at the base of plants, and dens in rock crevices. Other shelter types include holes and crevices in cutbanks along washes, burrows of other animals, piles of coarse woody debris, and human habitations and structures. Houses and dens are often maintained by successive generations of white-throated woodrats. Houses are built by white-throated woodrats at
8892-450: The energy made available from absorbed substances. Differences in that overhead cost are important influences on lifestyle, behavior, and even physical structures. Examples may be seen in humans, who differ considerably from other hominids (lack of hair, smaller jaws and musculature, different dentition, length of intestines, cooking, etc.). The major part of digestion takes place in the small intestine. The large intestine primarily serves as
9006-496: The environment surrounding the organism, where they break down an organic material, and some of the products diffuse back to the organism. Animals have a tube ( gastrointestinal tract ) in which internal digestion occurs, which is more efficient because more of the broken down products can be captured, and the internal chemical environment can be more efficiently controlled. Some organisms, including nearly all spiders , secrete biotoxins and digestive chemicals (e.g., enzymes) into
9120-520: The environments. In a channel transport system, several proteins form a contiguous channel traversing the inner and outer membranes of the bacteria. It is a simple system, which consists of only three protein subunits: the ABC protein , membrane fusion protein (MFP), and outer membrane protein . This secretion system transports various chemical species, from ions, drugs, to proteins of various sizes (20–900 kDa). The chemical species secreted vary in size from
9234-402: The extracellular environment prior to ingestion of the consequent "soup". In others, once potential nutrients or food is inside the organism , digestion can be conducted to a vesicle or a sac-like structure, through a tube, or through several specialized organs aimed at making the absorption of nutrients more efficient. Bacteria use several systems to obtain nutrients from other organisms in
9348-742: The factors in white-throated woodrat shelter-site selection in McDowell Mountain Regional Park was presence of teddy bear cholla . In the Cholla Garden in Joshua Tree National Park , white-throated woodrats depended on stands of jumping cholla (Cylindropuntia fulgida) for cover, and in the Lower Sonoran zone of Arizona, most white-throated woodrat dens were found at the bases of cholla and prickly-pear. In Guadalupe Mountains National Park , white-throated woodrat distribution may be limited more by
9462-482: The food further and this is combined with the churning action of the stomach. Mainly proteins are digested in stomach. The partially digested food enters the duodenum as a thick semi-liquid chyme . In the small intestine, the larger part of digestion takes place and this is helped by the secretions of bile , pancreatic juice and intestinal juice . The intestinal walls are lined with villi , and their epithelial cells are covered with numerous microvilli to improve
9576-421: The food; the electrolyte hydrogencarbonate ( HCO 3 ), which provides the ideal conditions of pH for amylase to work; and other electrolytes ( Na , K , Cl ). About 30% of starch is hydrolyzed into disaccharide in the oral cavity (mouth). After undergoing mastication and starch digestion, the food will be in the form of a small, round slurry mass called a bolus . It will then travel down
9690-417: The form of trypsinogen , which is activated in the duodenum by enterokinase to form trypsin. Trypsin then cleaves proteins to smaller polypeptides. Digestion of some fats can begin in the mouth where lingual lipase breaks down some short chain lipids into diglycerides . However fats are mainly digested in the small intestine. The presence of fat in the small intestine produces hormones that stimulate
9804-412: The gizzard churn and mix the mass of food and dirt. When the churning is complete, the glands in the walls of the gizzard add enzymes to the thick paste, which helps chemically breakdown the organic matter. By peristalsis , the mixture is sent to the intestine where friendly bacteria continue chemical breakdown. This releases carbohydrates, protein, fat, and various vitamins and minerals for absorption into
9918-645: The main foods eaten from the end of March until the end of summer. After honey mesquite lost its leaves, white-throated woodrats subsisted on stored beans, bark, and stems. Some white-throated woodrats store food in their houses. Of 30 white-throated woodrat dens found in Doña Ana County, New Mexico , 77% contained stored food. The average weight of stored food was 2.2 pounds (1.0 kg)/den, range 0.1 to 9.3 pounds (0.05–4.2 kg)/den. Most stored food consisted of mesquite beans and cacti and forb seeds. In general, white-throated woodrats collect food within
10032-571: The most commonly consumed plants across the white-throated woodrat's range include mesquite flowers, leaves, seeds, and bark, cacti flowers, stems, and fruits, and yucca leaves. Foods eaten by white-throated woodrats depend on availability. In Great Basin scrub desert and juniper woodlands in northern Arizona ( Coconino County ) white-throated woodrat diet was 29% yucca, 24% juniper, 7% rabbitbrush ( Chrysothamnus spp.), 6% sumac, 5% Apache-plume ( Fallugia spp.), 4% sagebrush ( Artemisia spp.), 4% saltbush, and 3% ephedra ( Ephedra spp.). In
10146-573: The outside that functions as both a mouth and an anus : waste and undigested matter is excreted through the mouth/anus, which can be described as an incomplete gut . In a plant such as the Venus flytrap that can make its own food through photosynthesis, it does not eat and digest its prey for the traditional objectives of harvesting energy and carbon, but mines prey primarily for essential nutrients (nitrogen and phosphorus in particular) that are in short supply in its boggy, acidic habitat. A phagosome
10260-431: The presence of Mexican woodrats (N. mexicana) and the southern plains woodrat (N. micropus) than by habitat limitations. In areas not inhabited by Mexican woodrats and southern plains woodrats, the white-throated woodrat constructed houses at bases of prickly-pears. In areas where white-throated woodrats and southern plains woodrats lived in close proximity, white-throated woodrat constructed houses under honey mesquite. In
10374-443: The regions where they are available. In the absence of rock crevices or caves, the dens are often built under trees or bushes. The pack rats will also use plant fragments, animal dung, and small rocks in building the den. The vast majority of the materials will be from a radius of several dozen yards of the nest. Woodrats often urinate on the debris piles; sugar and other substances in the urine crystallize as it dries out, creating
10488-669: The release of pancreatic lipase from the pancreas and bile from the liver which helps in the emulsification of fats for absorption of fatty acids . Complete digestion of one molecule of fat (a triglyceride ) results a mixture of fatty acids, mono- and di-glycerides, but no glycerol . In humans, dietary starches are composed of glucose units arranged in long chains called amylose, a polysaccharide . During digestion, bonds between glucose molecules are broken by salivary and pancreatic amylase , resulting in progressively smaller chains of glucose. This results in simple sugars glucose and maltose (2 glucose molecules) that can be absorbed by
10602-413: The release of more gastric juices. As protein enters the stomach, it binds to hydrogen ions, which raises the pH of the stomach. Inhibition of gastrin and gastric acid secretion is lifted. This triggers G cells to release gastrin , which in turn stimulates parietal cells to secrete gastric acid. Gastric acid is about 0.5% hydrochloric acid , which lowers the pH to the desired pH of 1–3. Acid release
10716-431: The secretion of saliva and its digestive enzymes. Food is formed into a bolus by the mechanical mastication and swallowed into the esophagus from where it enters the stomach through the action of peristalsis . Gastric juice contains hydrochloric acid and pepsin which would damage the walls of the stomach and mucus and bicarbonates are secreted for protection. In the stomach further release of enzymes break down
10830-406: The seed open with the sides of the beak. The mouth of the squid is equipped with a sharp horny beak mainly made of cross-linked proteins . It is used to kill and tear prey into manageable pieces. The beak is very robust, but does not contain any minerals, unlike the teeth and jaws of many other organisms, including marine species. The beak is the only indigestible part of the squid. The tongue
10944-400: The size of fecal pellets in pack rat middens. The size of woodrat pellet is proportional to the size of the woodrat. By measuring the pellets, the approximate size of the woodrat was determined based on data from a study of field-trapped woodrats. From Bergmann’s rule, differences in climate then can be determined. According to Bergmann’s rule , the body size of vertebrates is closely related to
11058-548: The small Escherichia coli peptide colicin V, (10 kDa) to the Pseudomonas fluorescens cell adhesion protein LapA of 900 kDa. A type III secretion system means that a molecular syringe is used through which a bacterium (e.g. certain types of Salmonella , Shigella , Yersinia ) can inject nutrients into protist cells. One such mechanism was first discovered in Y. pestis and showed that toxins could be injected directly from
11172-447: The small compounds that the body can use. In the human digestive system , food enters the mouth and mechanical digestion of the food starts by the action of mastication (chewing), a form of mechanical digestion, and the wetting contact of saliva . Saliva, a liquid secreted by the salivary glands , contains salivary amylase , an enzyme which starts the digestion of starch in the food. The saliva also contains mucus , which lubricates
11286-613: The small intestine. Lactase is an enzyme that breaks down the disaccharide lactose to its component parts, glucose and galactose . Glucose and galactose can be absorbed by the small intestine. Approximately 65 percent of the adult population produce only small amounts of lactase and are unable to eat unfermented milk-based foods. This is commonly known as lactose intolerance . Lactose intolerance varies widely by genetic heritage; more than 90 percent of peoples of east Asian descent are lactose intolerant, in contrast to about 5 percent of people of northern European descent. Sucrase
11400-399: The speedy application of medication into the cardiovascular system, bypassing the gastrointestinal tract. Teeth (singular tooth) are small whitish structures found in the jaws (or mouths) of many vertebrates that are used to tear, scrape, milk and chew food. Teeth are not made of bone, but rather of tissues of varying density and hardness, such as enamel, dentine and cementum. Human teeth have
11514-424: The stomach and duodenum in which 3 main enzymes, pepsin secreted by the stomach and trypsin and chymotrypsin secreted by the pancreas, break down food proteins into polypeptides that are then broken down by various exopeptidases and dipeptidases into amino acids . The digestive enzymes however are mostly secreted as their inactive precursors, the zymogens . For example, trypsin is secreted by pancreas in
11628-403: The stomach and gastrointestinal tract , and the process finishes with defecation. The human gastrointestinal tract is around 9 metres (30 feet) long. Food digestion physiology varies between individuals and upon other factors such as the characteristics of the food and size of the meal, and the process of digestion normally takes between 24 and 72 hours. Digestion begins in the mouth with
11742-435: The stomach is not buffered by food at this point and thus acts to inhibit parietal (secretes acid) and G cell (secretes gastrin) activity via D cell secretion of somatostatin . The gastric phase takes 3 to 4 hours. It is stimulated by distension of the stomach, presence of food in stomach and decrease in pH . Distention activates long and myenteric reflexes. This activates the release of acetylcholine , which stimulates
11856-490: The subspecies Neotoma albigula venusta in western Arizona, Sonora, and Baja California occur earlier: young are weaned between 27 and 40 days, and reach sexual maturity 80 to 87 days after birth. In Joshua Tree National Monument, California, young white-throated woodrats establish their own dens by August and September, several months after birth. Descriptions of the home range of the white-throated woodrat are lacking. The home range of 1 immature female white-throated woodrat on
11970-437: The tails of short-haired squirrels. In general, packrats' backs are notably a hybrid hue of brown and grey, but their underbelly tends to be a lighter shade. Woodrats reach their greatest diversity in the deserts of the western United States and northern Mexico. Several species are also found in the deciduous forest of the east coast, juniper woodlands in the southwest, oak woodlands along the coastal western United States and in
12084-537: The use of the multiprotein complexes listed above, gram-negative bacteria possess another method for release of material: the formation of outer membrane vesicles . Portions of the outer membrane pinch off, forming spherical structures made of a lipid bilayer enclosing periplasmic materials. Vesicles from a number of bacterial species have been found to contain virulence factors, some have immunomodulatory effects, and some can directly adhere to and intoxicate host cells. While release of vesicles has been demonstrated as
12198-622: The white-throated woodrat is 45 months, and according to Newton, maximum longevity is 72 months. The mating season of white-throated woodrats varies across their range. In Arizona, the mating season is from January to August. In Big Bend National Park, Texas, mating occurs at least from January to November and may occur year-round. In California, the mating season is in February and March, according to Rainey, and in March, April, and possibly May, according to Schwartz and Bleich. The mating system of
12312-425: The white-throated woodrat is polygynous. Gestation for white-throated woodrats lasts 37 to 38 days, and young are most often born in spring and early summer. In Arizona, mean litter sizes were 1.95 young/litter (n=93 litters) and 2.5 young/litter (n=27 litters). Young white-throated woodrats are weaned 62 to 72 days after birth and reach sexual maturity 166 to 176 days after birth. Weaning and sexual maturity of
12426-399: The year using new and old building materials. In Guadalupe Mountains National Park and the Lower Sonoran zone of Arizona, use of building materials depended on availability. Juniper leaves and berries were used most often in a pinyon-juniper woodland, and mesquite leaves and pods and Christmas cactus ( Cylindropuntia leptocaulis ) joints were used most often in a desert scrub habitat. In
12540-526: Was abundant; and juniper, pinyon pine, and oak twigs where they were abundant. Other items included horse, cow, and coyote dung, animal bones, stones, and human-discarded materials. Building materials are gathered near the white-throated woodrat's shelter. At McDowell Mountain Regional Park, Arizona, white-throated woodrats gathered 30% of house building materials within 33 feet (10 m) from their shelter. Houses and dens are altered and refurbished during
12654-453: Was generally greater in an active riparian channel and floodplain than a mesquite bosque that was 7 to 13 feet (2–4 m) above the channel and floodplain and not subject to flooding. The active riparian channel and floodplain was dominated by desert willow, velvet ash, Arizona sycamore, and velvet mesquite. The mesquite bosque was dominated by velvet mesquite, catclaw acacia, and broom snakeweed. Despite greater abundance of white-throated woodrat in
12768-482: Was more important than overstory species composition in influencing white-throated woodrat occurrence. The greatest densities of white-throated woodrat houses were on plots containing 376 to 750 overstory plants per hectare: White-throated woodrats prefer rocky areas within forested habitat, including ledges, slides, cliffs, and canyons. In a ponderosa pine forest on the Beaver Creek Watershed in
12882-451: Was probably selected for shelter least often because it is a single-stemmed tree with a tall canopy; organpipe cactus ( Stenocereus thurberi ) was probably selected most often because it is a multiple-stemmed plant with many cylindrical stems branching near the ground from a central trunk, providing more cover. In juniper woodlands in the high desert of southeastern Utah, white-throated woodrats occasionally denned under boulder crevices at
12996-419: Was very abundant and used for building material, even though plants were too small to shelter a white-throated woodrat den. Cover near the ground is an important criterion for white-throated woodrat shelter sites. In northern portions of their range, white-throated woodrats tend to construct houses at the bases of trees; in southern portions of their range, white-throated woodrats tend to construct houses at
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