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38-479: For over 20 years after construction, the lake was used for recreational boating, with half of the lake designated for watersports and the other half a no-wake zone for wildlife habitat and fishing. The lake was so popular that access was limited by the park's rangers to keep the boat traffic down on the lake on Saturday and Sunday afternoons. The lake's marina, snack bar, swimming area and boat ramps were all removed, and restrictions were placed on boat operation. Today,

76-400: A peptide which has been studied for use in treating ovarian cancer . Also, along with the bats and toothed whales , some species of shrews use echolocation . Unlike most other mammals, shrews lack zygomatic bones (also called the jugals ), so have incomplete zygomatic arches . The only terrestrial mammals known to echolocate are two genera ( Sorex and Blarina ) of shrews,

114-503: A big stone or tree trunk, they probably are not able to disentangle echo scenes, but rather derive information on habitat type from the overall call reverberations. This might be comparable to human hearing whether one calls into a beech forest or into a reverberant wine cellar. The 385 shrew species are placed in 26 genera, which are grouped into three living subfamilies: Crocidurinae ( white-toothed shrews ), Myosoricinae (African shrews), and Soricinae ( red-toothed shrews ). In addition,

152-480: A broad neocortex region of the brain, fur or hair , and three middle ear bones . These characteristics distinguish them from reptiles and birds , from which their ancestors diverged in the Carboniferous Period over 300 million years ago. Around 6,400 extant species of mammals have been described and divided into 27 orders . The largest orders of mammals, by number of species , are

190-536: A leash at all times. Hunting is allowed in season (for deer, turkey, and pheasant ) with a permit and there are several fishing piers along the lake, which are open outside of the bird migration seasons. The refuge also documents the area's human history. In 1865, the sternwheel steamboat Bertrand , bound for the Montana Territory , sank in the Missouri River. The boat and its cargo rested on

228-400: A year; in the tropics, they breed all year round; in temperate zones, they cease breeding only in the winter. Shrews have gestation periods of 17–32 days. The female often becomes pregnant within a day or so of giving birth, and lactates during her pregnancy, weaning one litter as the next is born. Shrews live 12 to 30 months. A characteristic behaviour observed in many species of shrew

266-1208: Is about 15 cm (6 in) long and weighs around 100 g ( 3 + 1 ⁄ 2  oz) The Etruscan shrew ( Suncus etruscus ), at about 3.5 cm ( 1 + 3 ⁄ 8  in) and 1.8 grams (28 grains), is the smallest known living terrestrial mammal. In general, shrews are terrestrial creatures that forage for seeds, insects, nuts, worms, and a variety of other foods in leaf litter and dense vegetation e.g. grass , but some specialise in climbing trees, living underground, living under snow , or even hunting in water. They have small eyes and generally poor vision , but have excellent senses of hearing and smell . They are very active animals, with voracious appetites. Shrews have unusually high metabolic rates , above that expected in comparable small mammals. For this reason, they need to eat almost constantly like moles . Shrews in captivity can eat 1 ⁄ 2 to 2 times their own body weight in food daily. They do not hibernate , but some species are capable of entering torpor . In winter, many species undergo morphological changes that drastically reduce their body weight. Shrews can lose between 30% and 50% of their body weight, shrinking

304-412: Is known as "caravanning". This is when a litter of young shrews form a line behind the mother, each gripping the shrew in front by the fur at the base of the tail. Shrews are unusual among mammals in a number of respects. Unlike most mammals, some species of shrews are venomous . Shrew venom is not conducted into the wound by fangs , but by grooves in the teeth. The venom contains various compounds, and

342-426: Is located five miles (eight kilometres) east of Blair, Nebraska . Access to the refuge is on U.S. Route 30 between Blair and Interstate 29 . Mammal A mammal (from Latin mamma  'breast') is a vertebrate animal of the class Mammalia ( / m ə ˈ m eɪ l i . ə / ). Mammals are characterized by the presence of milk -producing mammary glands for feeding their young,

380-572: Is primarily driven by human poaching and habitat destruction , primarily deforestation . Over 70% of mammal species are in the orders Rodentia , Chiroptera , and Eulipotyphla . Mammal classification has been through several revisions since Carl Linnaeus initially defined the class, and at present , no classification system is universally accepted. McKenna & Bell (1997) and Wilson & Reeder (2005) provide useful recent compendiums. Simpson (1945) provides systematics of mammal origins and relationships that had been taught universally until

418-426: Is the viviparous placental mammals , so named for the temporary organ ( placenta ) used by offspring to draw nutrition from the mother during gestation . Most mammals are intelligent , with some possessing large brains, self-awareness , and tool use . Mammals can communicate and vocalize in several ways, including the production of ultrasound , scent marking , alarm signals , singing , echolocation ; and, in

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456-595: The Boreoeutheria magnorder . Shrews have sharp, spike-like teeth, whereas rodents have gnawing front incisor teeth. Shrews are distributed almost worldwide . Among the major tropical and temperate land masses, only New Guinea , Australia , New Zealand , and South America have no native shrews. However, as a result of the Great American Interchange , South America does have a relatively recently naturalised population, present only in

494-473: The Cretaceous . The relationships between these three lineages is contentious, and all three possible hypotheses have been proposed with respect to which group is basal . These hypotheses are Atlantogenata (basal Boreoeutheria), Epitheria (basal Xenarthra) and Exafroplacentalia (basal Afrotheria). Boreoeutheria in turn contains two major lineages— Euarchontoglires and Laurasiatheria . Estimates for

532-564: The International Union for Conservation of Nature (IUCN) completed a five-year Global Mammal Assessment for its IUCN Red List , which counted 5,488 species. According to research published in the Journal of Mammalogy in 2018, the number of recognized mammal species is 6,495, including 96 recently extinct. The word " mammal " is modern, from the scientific name Mammalia coined by Carl Linnaeus in 1758, derived from

570-556: The Latin mamma ("teat, pap"). In an influential 1988 paper, Timothy Rowe defined Mammalia phylogenetically as the crown group of mammals, the clade consisting of the most recent common ancestor of living monotremes ( echidnas and platypuses ) and therian mammals ( marsupials and placentals ) and all descendants of that ancestor. Since this ancestor lived in the Jurassic period, Rowe's definition excludes all animals from

608-606: The biological classification scheme used, are the primates : apes , monkeys , and lemurs ; the Cetartiodactyla : whales and even-toed ungulates ; and the Carnivora which includes cats , dogs , weasels , bears , seals , and allies. According to Mammal Species of the World , 5,416 species were identified in 2006. These were grouped into 1,229  genera , 153  families and 29 orders. In 2008,

646-406: The dominant terrestrial animal group from 66 million years ago to the present. The basic mammalian body type is quadrupedal , with most mammals using four limbs for terrestrial locomotion ; but in some, the limbs are adapted for life at sea , in the air , in trees or underground . The bipeds have adapted to move using only the two lower limbs, while the rear limbs of cetaceans and

684-446: The order Eulipotyphla . True shrews are not to be confused with treeshrews , otter shrews , elephant shrews , West Indies shrews , or marsupial shrews , which belong to different families or orders. Although its external appearance is generally that of a long-nosed mouse, a shrew is not a rodent , as mice are. It is, in fact, a much closer relative of hedgehogs and moles; shrews are related to rodents only in that both belong to

722-428: The rodents , bats , and Eulipotyphla (including hedgehogs , moles and shrews ). The next three are the primates (including humans , monkeys and lemurs ), the even-toed ungulates (including pigs , camels , and whales ), and the Carnivora (including cats , dogs , and seals ). Mammals are the only living members of Synapsida ; this clade , together with Sauropsida (reptiles and birds), constitutes

760-439: The sea cows are mere internal vestiges . Mammals range in size from the 30–40 millimetres (1.2–1.6 in) bumblebee bat to the 30 metres (98 ft) blue whale —possibly the largest animal to have ever lived. Maximum lifespan varies from two years for the shrew to 211 years for the bowhead whale . All modern mammals give birth to live young, except the five species of monotremes , which lay eggs. The most species-rich group

798-835: The tenrecs of Madagascar , bats , and the solenodons . These include the Eurasian or common shrew ( Sorex araneus ) and the American vagrant shrew ( Sorex vagrans ) and northern short-tailed shrew ( Blarina brevicauda ). These shrews emit series of ultrasonic squeaks. By nature the shrew sounds, unlike those of bats, are low-amplitude, broadband, multiharmonic, and frequency modulated. They contain no "echolocation clicks" with reverberations and would seem to be used for simple, close-range spatial orientation. In contrast to bats, shrews use echolocation only to investigate their habitats rather than additionally to pinpoint food. Except for large and thus strongly reflecting objects, such as

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836-492: The case of humans, complex language . Mammals can organize themselves into fission–fusion societies , harems , and hierarchies —but can also be solitary and territorial . Most mammals are polygynous , but some can be monogamous or polyandrous . Domestication of many types of mammals by humans played a major role in the Neolithic Revolution , and resulted in farming replacing hunting and gathering as

874-419: The chewing molars at the back of the mouth, the teeth of shrews are small and peg-like, and may be reduced in number. The dental formula of shrews is: 3.1.1-3.3 1-2.0-1.1.3 Shrews are fiercely territorial, driving off rivals, and coming together only to mate. Many species dig burrows for catching food and hiding from predators , although this is not universal. Female shrews can have up to 10 litters

912-812: The clade originating with the last common ancestor of Sinoconodon and living mammals. The earliest-known synapsid satisfying Kemp's definitions is Tikitherium , dated 225 Ma , so the appearance of mammals in this broader sense can be given this Late Triassic date. However, this animal may have actually evolved during the Neogene. As of the early 21st century, molecular studies based on DNA analysis have suggested new relationships among mammal families. Most of these findings have been independently validated by retrotransposon presence/absence data . Classification systems based on molecular studies reveal three major groups or lineages of placental mammals— Afrotheria , Xenarthra and Boreoeutheria —which diverged in

950-444: The closest thing to an official classification of mammals, despite its known issues. Most mammals, including the six most species-rich orders , belong to the placental group. The three largest orders in numbers of species are Rodentia : mice , rats , porcupines , beavers , capybaras , and other gnawing mammals; Chiroptera : bats; and Eulipotyphla : shrews , moles , and solenodons . The next three biggest orders, depending on

988-488: The contents of the venom glands of the American short-tailed shrew are sufficient to kill 200 mice by intravenous injection. One chemical extracted from shrew venom may be potentially useful in the treatment of high blood pressure, while another compound may be useful in the treatment of some neuromuscular diseases and migraines . The saliva of the northern short-tailed shrew ( Blarina brevicauda ) contains soricidin ,

1026-1374: The divergence times between these three placental groups range from 105 to 120 million years ago, depending on the type of DNA used (such as nuclear or mitochondrial ) and varying interpretations of paleogeographic data. Monotremata Marsupialia Xenarthra Afrotheria Glires Euarchonta [REDACTED] Eulipotyphla Chiroptera Pholidota Carnivora [REDACTED] Perissodactyla [REDACTED] Artiodactyla [REDACTED] Monotremata [REDACTED] Paucituberculata [REDACTED] Didelphimorphia [REDACTED] Microbiotheria Notoryctemorphia [REDACTED] Peramelemorphia [REDACTED] Dasyuromorphia [REDACTED] Diprotodontia [REDACTED] Cingulata [REDACTED] Pilosa [REDACTED] Hyracoidea [REDACTED] Sirenia [REDACTED] Proboscidea [REDACTED] Tubulidentata [REDACTED] Macroscelidea [REDACTED] Afrosoricida [REDACTED] Eulipotyphla [REDACTED] Chiroptera [REDACTED] Pholidota [REDACTED] Carnivora [REDACTED] Perissodactyla [REDACTED] Artiodactyla [REDACTED] Scandentia [REDACTED] Lagomorpha [REDACTED] Shrew Shrews ( family Soricidae ) are small mole -like mammals classified in

1064-585: The earlier Triassic , despite the fact that Triassic fossils in the Haramiyida have been referred to the Mammalia since the mid-19th century. If Mammalia is considered as the crown group, its origin can be roughly dated as the first known appearance of animals more closely related to some extant mammals than to others. Ambondro is more closely related to monotremes than to therian mammals while Amphilestes and Amphitherium are more closely related to

1102-451: The end of the 20th century. However, since 1945, a large amount of new and more detailed information has gradually been found: The paleontological record has been recalibrated, and the intervening years have seen much debate and progress concerning the theoretical underpinnings of systematization itself, partly through the new concept of cladistics . Though fieldwork and lab work progressively outdated Simpson's classification, it remains

1140-668: The larger Amniota clade. Early synapsids are referred to as " pelycosaurs ." The more advanced therapsids became dominant during the Guadalupian . Mammals originated from cynodonts , an advanced group of therapsids, during the Late Triassic to Early Jurassic . Mammals achieved their modern diversity in the Paleogene and Neogene periods of the Cenozoic era, after the extinction of non-avian dinosaurs , and have been

1178-459: The northern Andes . The shrew family has 385 known species, making it the fourth-most species-diverse mammal family. The only mammal families with more species are the muroid rodent families ( Muridae and Cricetidae ) and the bat family Vespertilionidae . All shrews are tiny, most no larger than a mouse. The largest species is the Asian house shrew ( Suncus murinus ) of tropical Asia, which

DeSoto National Wildlife Refuge - Misplaced Pages Continue

1216-716: The primary source of food for humans. This led to a major restructuring of human societies from nomadic to sedentary, with more co-operation among larger and larger groups, and ultimately the development of the first civilizations . Domesticated mammals provided, and continue to provide, power for transport and agriculture, as well as food ( meat and dairy products ), fur , and leather . Mammals are also hunted and raced for sport, kept as pets and working animals of various types, and are used as model organisms in science. Mammals have been depicted in art since Paleolithic times, and appear in literature, film, mythology, and religion. Decline in numbers and extinction of many mammals

1254-502: The refuge is home to around 30 mammal species, including white-tailed deer , beavers , opossums , raccoons , fox squirrels , muskrats and coyotes . Many bird species also inhabit the refuge, such as bald eagles , great blue herons , egrets , pelicans , turkeys and cardinals . The refuge is also a major stopover on the Central Flyway bird migration route; the population of migratory birds increases substantially in

1292-539: The river bottom until 1968, when the wreck was rediscovered. Over 500,000 items were excavated from the wreck; many of them were in excellent condition. Catalogue numbers are now in the upper 5000's, each number sometimes only having one related object, or, in the case of nails, tens of thousands. A visitor center in the refuge displays many of these items. The Bertrand site is listed on the National Register of Historic Places . DeSoto National Wildlife Refuge

1330-426: The size of bones, skull, and internal organs. Whereas rodents have gnawing incisors that grow throughout life, the teeth of shrews wear down throughout life, a problem made more extreme because they lose their milk teeth before birth, so have only one set of teeth throughout their lifetimes. In some species, exposed areas of the teeth are dark red due to the presence of iron in the tooth enamel. The iron reinforces

1368-461: The spring and fall months. The numbers of snow geese used to frequently be in the hundreds of thousands, but for unknown reasons has substantially dropped for only a few thousand a year (not at once). The population of Canada geese that stopped at the lake before it was channelized is once again rising. Several miles of nature trails provide access to the varied landscapes of the refuge. Dogs are permitted only under physical restrictive control of

1406-401: The surfaces that are exposed to the most stress, which helps prolong the life of the teeth. This adaptation is not found in species with lower metabolism, which do not have to eat as much and therefore do not wear down the enamel to the same degree. The only other mammals' teeth with pigmented enamel are the incisors of rodents. Apart from the first pair of incisors, which are long and sharp, and

1444-548: The therians; as fossils of all three genera are dated about 167 million years ago in the Middle Jurassic , this is a reasonable estimate for the appearance of the crown group. T. S. Kemp has provided a more traditional definition: " Synapsids that possess a dentary – squamosal jaw articulation and occlusion between upper and lower molars with a transverse component to the movement" or, equivalently in Kemp's view,

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