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81-615: Pinnipeds (pronounced / ˈ p ɪ n ɪ ˌ p ɛ d z / ), commonly known as seals , are a widely distributed and diverse clade of carnivorous , fin -footed, semiaquatic , mostly marine mammals . They comprise the extant families Odobenidae (whose only living member is the walrus ), Otariidae (the eared seals: sea lions and fur seals ), and Phocidae (the earless seals, or true seals), with 34 extant species and more than 50 extinct species described from fossils . While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as
162-422: A coastal strip . A second example, some species of bird depend on water, usually a river, swamp, etc., or water related forest and live in a river corridor . A separate example of a river corridor would be a river corridor that includes the entire drainage, having the edge of the range delimited by mountains, or higher elevations; the river itself would be a smaller percentage of this entire wildlife corridor , but
243-671: A monophyletic origin. A 2021 genetic study found that pinnipeds are more closely related to musteloids. Pinnipeds split from other caniforms 50 million years ago ( mya ) during the Eocene . The earliest fossils of pinnipeds date back to the Late Oligocene . Fossil animals representing basal lineages include Puijila , of the Early Miocene in Arctic Canada. It resembled a modern otter, but shows evidence of quadrupedal swimming—retaining
324-616: A monophyletic group (descended from one ancestor). Pinnipeds belong to the suborder Caniformia of the order Carnivora ; their closest living relatives are musteloids ( weasels , raccoons , skunks and red pandas ), having diverged about 50 million years ago. Seals range in size from the 1 m (3 ft 3 in) and 45 kg (100 lb) Baikal seal to the 5 m (16 ft) and 3,200 kg (7,100 lb) southern elephant seal . Several species exhibit sexual dimorphism . They have streamlined bodies and four limbs that are modified into flippers . Though not as fast in
405-559: A bio-climate range, or bio-climate envelope. The envelope can range from a local to a global scale or from a density independence to dependence. The hierarchical model takes into consideration the requirements, impacts or resources as well as local extinctions in disturbance factors. Models can integrate the dispersal/migration model, the disturbance model, and abundance model. Species distribution models (SDMs) can be used to assess climate change impacts and conservation management issues. Species distribution models include: presence/absence models,
486-420: A desire to facilitate social behaviour. Dogs' close relationship with humans also renders dogs reliant on humans, even for basic needs. Barking can be used as a way to attract attention, and any positive response exhibited by the owners reinforces the behaviour. For example, if a dog barks to get food and the owner feeds it, they are conditioned to continue said behaviour. The purposes of barking by domestic dogs
567-615: A few, such as the leopard seal , feed on large vertebrates, such as penguins and other seals. Walruses are specialized for feeding on bottom-dwelling mollusks . Male pinnipeds typically mate with more than one female ( polygyny ), though the degree of polygyny varies with the species. The males of land-breeding species tend to mate with a greater number of females than those of ice breeding species . Male pinniped strategies for reproductive success vary between defending females, defending territories that attract females and performing ritual displays or lek mating . Pups are typically born in
648-499: A form of aquatic locomotion that led to those employed by modern pinnipeds. Potamotherium , which lived in the same period in Europe, was similar to Puijila but more aquatic. The braincase of Potamotherium shows evidence that it used its whiskers to hunt, like modern seals. Both Puijila and Potamotherium fossils have been found in lake deposits, suggesting that seal ancestors were originally adapted for fresh water. Enaliarctos ,
729-419: A fossil species of late Oligocene /early Miocene (24–22 mya) California , closely resembled modern pinnipeds; it was adapted to an aquatic life with flippers and a flexible spine. Its teeth were more like land predators in that they were more adapted for shearing . Its hind-flippers may have allowed it to walk on land, and it probably did not leave coastal areas as much as its modern relatives. Enaliarctos
810-463: A greater number of successful kills. A prime example of clumped distribution due to patchy resources is the wildlife in Africa during the dry season; lions, hyenas, giraffes, elephants, gazelles, and many more animals are clumped by small water sources that are present in the severe dry season. It has also been observed that extinct and threatened species are more likely to be clumped in their distribution on
891-581: A layer of fat, or blubber , under the skin to keep warm in cold water, and, other than the walrus, all species are covered in fur. Although pinnipeds are widespread, most species prefer the colder waters of the Northern and Southern Hemispheres. They spend most of their lives in water, but come ashore to mate, give birth, molt or to avoid ocean predators, such as sharks and orcas . Seals mainly live in marine environments but can also be found in fresh water. They feed largely on fish and marine invertebrates ;
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#1732858084849972-437: A main range for the species (contiguous range) or are in an isolated geographic range and be a disjunct range. Birds leaving the area, if they migrate , would leave connected to the main range or have to fly over land not connected to the wildlife corridor; thus, they would be passage migrants over land that they stop on for an intermittent, hit or miss, visit. On large scales, the pattern of distribution among individuals in
1053-408: A mixture of atonal and tonal . Also, barking is almost exclusively used for giving warnings. Warn-barking in a homotypical sequence and a kind of "warn-howling" in a heterotypical one have also been observed. The bark-howling starts with several barks and then fades into a rising and ebbing howl and is probably, similarly to coughing, used to warn the puppies and members of the pack. Dingoes also emit
1134-536: A phylogeny. The reasoning behind this is that they share traits that increase vulnerability to extinction because related taxa are often located within the same broad geographical or habitat types where human-induced threats are concentrated. Using recently developed complete phylogenies for mammalian carnivores and primates it has been shown that in the majority of instances threatened species are far from randomly distributed among taxa and phylogenetic clades and display clumped distribution. A contiguous distribution
1215-687: A plantation. Random distribution, also known as unpredictable spacing, is the least common form of distribution in nature and occurs when the members of a given species are found in environments in which the position of each individual is independent of the other individuals: they neither attract nor repel one another. Random distribution is rare in nature as biotic factors, such as the interactions with neighboring individuals, and abiotic factors, such as climate or soil conditions, generally cause organisms to be either clustered or spread. Random distribution usually occurs in habitats where environmental conditions and resources are consistent. This pattern of dispersion
1296-531: A population is clumped. On small scales, the pattern may be clumped, regular, or random. Clumped distribution , also called aggregated distribution , clumped dispersion or patchiness , is the most common type of dispersion found in nature. In clumped distribution, the distance between neighboring individuals is minimized. This type of distribution is found in environments that are characterized by patchy resources. Animals need certain resources to survive, and when these resources become rare during certain parts of
1377-486: A result of their domestication . Domestication can alter a species and affect its physical and physiological characteristics. Domesticated breeds show vast physical differences from their wild counterparts, an evolution that suggests neoteny , or the retention of juvenile characteristics in adults. The behaviour of adult dogs also shows puppy-like characteristics: dogs act submissive, whine, and bark often. The frequency of barking in dogs compared to wolves could also be
1458-459: A sort of "wailing" sound, which they use most often when approaching a water hole, probably to warn already present dingoes. According to current knowledge, it is impossible to get Australian dingoes to bark more often by making them associate with other domestic dogs. However, Alfred Brehm reported a dingo that learned the more "typical" form of barking and knew how to use it, while its brother did not. Whether dingoes bark or bark-howl less overall
1539-470: A species is distributed. For example, biotic factors in a quail's environment would include their prey (insects and seeds), competition from other quail, and their predators, such as the coyote. An advantage of a herd, community, or other clumped distribution allows a population to detect predators earlier, at a greater distance, and potentially mount an effective defense. Due to limited resources, populations may be evenly distributed to minimize competition, as
1620-697: A trigger or the dog lacking exercise or mental stimulation. Reasons for excessive barking can be, among others, pain, fear, boredom, frustration, separation anxiety or territorial behaviour (warning about potential threats). Different kinds of barking require different approaches to reduction. Common approaches are: If all other methods have been tried, a last effort is using a bark collar. These collars might release an unpleasant smell or mild to painful shock. Various bark collars have been praised and criticized; some are considered inhumane by various people and groups. Critics consider them torturous and compare their use to electrocution . However, most Societies for
1701-409: A whole (range). Species distribution is not to be confused with dispersal , which is the movement of individuals away from their region of origin or from a population center of high density . In biology , the range of a species is the geographical area within which that species can be found. Within that range, distribution is the general structure of the species population , while dispersion
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#17328580848491782-754: Is a controversial topic. While barking is suggested to be "non-communicative", data suggests that it may indeed be a means of expression that became increasingly sophisticated during domestication. Due to the lack of consensus over whether or not dogs communicate using their barks, not much research has been done to categorize the different types of barking in dogs. Some existing research has been criticized by Feddersen-Petersen as "lack[ing] objectivity". Using sonographic methods, Feddersen-Petersen identified several distinct types of barks, then analysed them for meanings, functions, and emotions. He separated dog barks into subgroups based on said sonographic data: Not all breeds demonstrate every subgroup of barking. Instead, there
1863-508: Is also a verb that describes the sound of many canids . There is no precise, consistent, and functional acoustic definition for barking, but researchers classify barks according to several criteria. Researchers at the University of Massachusetts Amherst and Hampshire College have defined a bark as a short, abrupt vocalization that is relatively loud and high-pitched, changes in frequency, and often repeats rapidly in succession. Dog barking
1944-400: Is because of their massive ankle bones and flatter heels. In water, true seals rely on the side-to-side motion of their hind-flippers and lower body to move forward. The phocid's skull has thickened mastoids , puffed up entotympanic bones , nasal bones with a pointed tip in the back and a non-existent supraorbital foramen. The hip has a more converse ilium . A 2006 molecular study supports
2025-486: Is characterized by the lack of any strong social interactions between species. For example; When dandelion seeds are dispersed by wind, random distribution will often occur as the seedlings land in random places determined by uncontrollable factors. Oyster larvae can also travel hundreds of kilometers powered by sea currents, which can result in their random distribution. Random distributions exhibit chance clumps (see Poisson clumping ). There are various ways to determine
2106-426: Is distinct from wolf barking. Wolf barks represent only 2.4% of all wolf vocalizations, in warning, defense, and protest. In contrast, dogs bark in many social situations, with acoustic communication in dogs being described as hypertrophic . While wolf barks tend to be brief and isolated, dog barking is often repetitive. One hypothesis for why dogs bark more than wolves is that dogs developed vocal communication as
2187-654: Is equal to 1, the population is found to be randomly distributed. If it is significantly greater than 1, the population is found to be clumped distribution. Finally, if the ratio is significantly less than 1, the population is found to be evenly distributed. Typical statistical tests used to find the significance of the variance/mean ratio include Student's t-test and chi squared . However, many researchers believe that species distribution models based on statistical analysis, without including ecological models and theories, are too incomplete for prediction. Instead of conclusions based on presence-absence data, probabilities that convey
2268-624: Is found in forests, where competition for sunlight produces an even distribution of trees. One key factor in determining species distribution is the phenology of the organism. Plants are well documented as examples showing how phenology is an adaptive trait that can influence fitness in changing climates. Physiology can influence species distributions in an environmentally sensitive manner because physiology underlies movement such as exploration and dispersal . Individuals that are more disperse-prone have higher metabolism, locomotor performance, corticosterone levels, and immunity. Humans are one of
2349-421: Is one in which individuals are closer together than they would be if they were randomly or evenly distributed, i.e., it is clumped distribution with a single clump. Less common than clumped distribution, uniform distribution, also known as even distribution, is evenly spaced. Uniform distributions are found in populations in which the distance between neighboring individuals is maximized. The need to maximize
2430-404: Is seen in juvenile animals that are immobile and strongly dependent upon parental care. For example, the bald eagle 's nest of eaglets exhibits a clumped species distribution because all the offspring are in a small subset of a survey area before they learn to fly. Clumped distribution can be beneficial to the individuals in that group. However, in some herbivore cases, such as cows and wildebeests,
2511-493: Is significant variance in vocalization between different breeds. Poodles show the least of all barking subunits. Barking in wolves was observed as less diverse. For example, wolf barks are rarely harmonic, tending instead to be noisy. There is some evidence that humans can determine the suspected emotions of dogs while listening to barks emitted during specific situations. Humans scored the emotions of dogs performing these barks very similarly and in ways that made sense according to
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2592-460: Is that a species will occur there also; this leads to a relationship between habitat suitability and species occurrence. Species distribution can be predicted based on the pattern of biodiversity at spatial scales. A general hierarchical model can integrate disturbance, dispersal and population dynamics. Based on factors of dispersal, disturbance, resources limiting climate, and other species distribution, predictions of species distribution can create
2673-411: Is the manner in which a biological taxon is spatially arranged. The geographic limits of a particular taxon's distribution is its range , often represented as shaded areas on a map. Patterns of distribution change depending on the scale at which they are viewed, from the arrangement of individuals within a small family unit, to patterns within a population, or the distribution of the entire species as
2754-466: Is the variation in its population density . Range is often described with the following qualities: Disjunct distribution occurs when two or more areas of the range of a taxon are considerably separated from each other geographically. Distribution patterns may change by season , distribution by humans, in response to the availability of resources, and other abiotic and biotic factors. There are three main types of abiotic factors: An example of
2835-440: Is unknown. The extinct Hare Indian dog of northern Canada was not known to bark in its native homeland, though puppies born in Europe learned how to imitate the barking of other dogs. When hurt or afraid, it howled like a wolf, and when curious, it made a sound described as a growl building up to a howl. The Basenji of central Africa produces a yodel -like sound due to its unusually shaped larynx. This trait also gives
2916-719: The Caribbean monk seal have become extinct in the past century, while the Mediterranean monk seal and Hawaiian monk seal are ranked as endangered by the International Union for Conservation of Nature . Besides hunting, pinnipeds also face threats from accidental trapping , marine pollution , climate change and conflicts with local people. The name "pinniped" derives from the Latin words pinna ' fin ' and pes, pedis ' foot ' . The common name "seal" originates from
2997-976: The Old English word seolh , which is in turn derived from the Proto-Germanic * selkhaz . Bearded seal Hooded seal Ringed seal Baikal seal Caspian seal Spotted seal Harbor seal Grey seal Ribbon seal Harp seal Weddell seal Leopard seal Crabeater seal Ross seal Southern elephant seal Northern elephant seal Mediterranean monk seal Hawaiian monk seal Northern fur seal Steller sea lion California sea lion Galápagos sea lion South American sea lion Australian sea lion New Zealand sea lion Brown fur seal Subantarctic fur seal Antarctic fur seal Guadalupe fur seal Juan Fernández fur seal Antipodean fur seal Galápagos fur seal South American fur seal Walrus The German naturalist Johann Karl Wilhelm Illiger
3078-506: The acoustic structure of a bark "[varies] considerably with context." These studies suggest that barks are more than just random sounds, and hold some communicative purpose. ‹The template How-to is being considered for merging .› Barking is a normal behaviour for dogs. What counts as excessive barking is a subjective idea. Excessive dog barking can be a nuisance and a common problem that dog owners or their neighbors may face. Excessive barking indicates an underlying problem,
3159-660: The nasal bones , with a large and flattened supraorbital foramen . An extra spine splits the supraspinatous fossa and bronchi that are divided in the front. Otariids consist of two types: sea lions and fur seals ; the latter typically being smaller, with pointier snouts, longer fore-flippers and heavier fur coats . Five genera and seven species (one now extinct) of sea lion are known to exist, while two genera and nine species of fur seal exist. While sea lions and fur seals have historically been considered separate subfamilies (Otariinae and Arctocephalinae respectively), genetic and molecular evidence has refuted this, indicating that
3240-543: The northern fur seal is basal to other otariids and the Australian sea lion and New Zealand sea lion are more closely related to Arctocephalus than to other sea lions. Odobenidae has only one living member: the walrus . This animal is noticeable from its larger size (exceeded only by the elephant seals ), nearly hairless skin, flattened snout and long upper canines , known as tusks . Like otariids, walruses can walk on land with their hind limbs. When moving in water,
3321-541: The orbital wall . The extinct family Desmatophocidae lived 23–10 mya in the North Pacific. They had long skulls that with large orbits, interlocked zygomatic bones and rounded molars and premolars . They also were sexually dimorphic and may have been capable of swimming with both or either pair of flippers. They are grouped with modern pinnipeds, but there is debate as to whether they are more closely related to phocids or to otariids and walruses. The ancestors of
Pinniped - Misplaced Pages Continue
3402-484: The voice box so that a barking dog will make a significantly reduced noise . It is considered a last resort by some owners claiming that it is better than euthanasia , seizure, or legal problems if the matter has proven incapable of being corrected any other way. Debarking is illegal in many European states and is opposed by animal welfare organizations. The Huntaway is a working dog that has been selectively bred to drive stock (usually sheep) by using its voice. It
3483-484: The 1 m (3 ft 3 in) and 45 kg (100 lb) Baikal seal to the 5 m (16 ft) and 3,200 kg (7,100 lb) southern elephant seal . Overall, they tend to be larger than other carnivores. Several species have male-biased sexual dimorphism that depends on how polygynous a species is: highly polygynous species like elephant seals are extremely sexually dimorphic, while less polygynous species have males and females that are closer in size, or, in
3564-560: The Americas. The map gallery Gridded Species Distribution contains sample maps for the Species Grids data set. These maps are not inclusive but rather contain a representative sample of the types of data available for download: Bark (sound) A bark is a sound most often produced by dogs . Other animals that make this noise include, but are not limited to, wolves , coyotes , foxes , seals , frogs , and barking owls . "Bark"
3645-680: The Basenji the nickname "Barkless Dog". Besides dogs and wolves, other canines like coyotes and jackals can bark. Their barks are similar to those of wolves and dogs. The warning bark of a fox is higher and more drawn out than barks of other canids. There are non-canine species with vocalizations that may be described as barking. Because the alarm call of the muntjac resembles a dog's bark, they are sometimes known as "barking deer". Eared seals are also known to bark. Prairie dogs employ complex communication involving barks and rhythmic chirps. Various bird species produce vocalizations that include
3726-676: The North Atlantic, and likely reached the Pacific via the Central American Seaway . Phocines mainly stayed in the Northern Hemisphere, while the monachines diversified southward. The lineages of Otariidae and Odobenidae split around 20 mya. The earliest fossil records of otariids are in North Pacific and dated to around 11 mya. Early fossil genera include Pithanotaria and Thalassoleon . The Callorhinus lineage split
3807-527: The Otarioidea and Phocidea diverged around 25 mya. Phocids are known to have existed for at least 15 million years, and molecular evidence supports a divergence of the Monachinae and Phocinae lineages around this time. The fossil genera Monotherium and Leptophoca of southeastern North America represent the earliest members of Monachinae and Phocinae respectively. Both lineages may have originated in
3888-484: The Prevention of Cruelty to Animals agree that in a last resort an electric collar is better than euthanasia if it comes to an ultimatum, for a stubborn dog that will not stop any other way. Most agree that understanding the communication and retraining by reward is the most effective and humane method. The controversial surgical procedure known as 'debarking' or 'bark softening' is a veterinary procedure for modifying
3969-462: The Variance/Mean ratio method, data is collected from several random samples of a given population. In this analysis, it is imperative that data from at least 50 sample plots is considered. The number of individuals present in each sample is compared to the expected counts in the case of random distribution. The expected distribution can be found using Poisson distribution . If the variance/mean ratio
4050-452: The body. Seals are unique among carnivorans in that their orbital walls are mostly shaped by the maxilla and are not contained by certain facial bones. Compared to land carnivores, pinnipeds have fewer teeth, which are pointed and cone-shaped. They are adapted for holding onto slippery prey rather than shearing meat like the carnassials of other carnivorans. The walrus has unique tusks which are long upper canines. Pinnipeds range in size from
4131-560: The case of Antarctic seals, females are moderately bigger. Males of sexually dimorphic species also tend to have secondary sex characteristics , such as larger or more prominent heads, necks, chests, crests , noses/ proboscises and canine teeth as well as thicker fur and manes. Though more polygynous species tend to be sexually dimorphic, some evidence suggests that size differences between the sexes originated due to ecological differences, with polygyny developing later. Range (biology) Species distribution , or species dispersion ,
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#17328580848494212-494: The complex songs of Weddell seals . The meat, blubber and skin of pinnipeds have traditionally been used by indigenous peoples of the Arctic . Seals have been depicted in various cultures worldwide. They are commonly kept in captivity and are even sometimes trained to perform tricks and tasks. Once relentlessly hunted by commercial industries for their products, seals are now protected by international law. The Japanese sea lion and
4293-468: The context. In one example, when subjects were played a recording of a dog tied alone to a tree, a situation in which one could infer that the dog would be distressed, the human listeners tended to rank the bark as having a high level of despair. Some suggest that this may be evidence that dog barks have evolved to be a form of communication with humans, since humans can determine a dog's needs by listening to their vocalizations. Further studies have found that
4374-517: The corridor is created because of the river. A further example of a bird wildlife corridor would be a mountain range corridor. In the U.S. of North America, the Sierra Nevada range in the west, and the Appalachian Mountains in the east are two examples of this habitat, used in summer, and winter, by separate species, for different reasons. Bird species in these corridors are connected to
4455-757: The creosote bushes in the southwestern region of the United States. Salvia leucophylla is a species in California that naturally grows in uniform spacing. This flower releases chemicals called terpenes which inhibit the growth of other plants around it and results in uniform distribution. This is an example of allelopathy , which is the release of chemicals from plant parts by leaching, root exudation, volatilization, residue decomposition and other processes. Allelopathy can have beneficial, harmful, or neutral effects on surrounding organisms. Some allelochemicals even have selective effects on surrounding organisms; for example,
4536-448: The dispersal/migration models, disturbance models, and abundance models. A prevalent way of creating predicted distribution maps for different species is to reclassify a land cover layer depending on whether or not the species in question would be predicted to habit each cover type. This simple SDM is often modified through the use of range data or ancillary information, such as elevation or water distance. Recent studies have indicated that
4617-420: The distance is recorded twice, once for each individual. To receive accurate results, it is suggested that the number of distance measurements is at least 50. The average distance between nearest neighbors is compared to the expected distance in the case of random distribution to give the ratio: If this ratio R is equal to 1, then the population is randomly dispersed. If R is significantly greater than 1,
4698-476: The distribution pattern of species. The Clark–Evans nearest neighbor method can be used to determine if a distribution is clumped, uniform, or random. To utilize the Clark–Evans nearest neighbor method, researchers examine a population of a single species. The distance of an individual to its nearest neighbor is recorded for each individual in the sample. For two individuals that are each other's nearest neighbor,
4779-491: The diversity, distribution and abundance of life in the oceans. Marine Life has become largely affected by increasing effects of global climate change . This study shows that as the ocean temperatures rise species are beginning to travel into the cold and harsh Arctic waters. Even the snow crab has extended its range 500 km north. Biotic factors such as predation, disease, and inter- and intra-specific competition for resources such as food, water, and mates can also affect how
4860-465: The division of phocids into two monophyletic subfamilies: Monachinae, which consists of elephant seals, monk seals and Antarctic seals ; and Phocinae, which consists of all the rest. One popular hypothesis suggested that pinnipeds are diphyletic (descended from two ancestral lines), with walruses and otariids sharing a recent common ancestor with bears ; and phocids sharing one with Musteloidea . However, morphological and molecular evidence support
4941-533: The earliest, followed by the Eumetopias / Zalophus lineage and then the rest, which colonized the Southern Hemisphere. The earliest fossils of Odobenidae— Prototaria of Japan and Proneotherium of Oregon—date to 18–16 mya. These primitive walruses had normal sized canines and fed on fish instead of mollusks. Later taxa like Gomphotaria , Pontolis and Dusignathus had longer canines on both
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#17328580848495022-595: The effects of abiotic factors on species distribution can be seen in drier areas, where most individuals of a species will gather around water sources, forming a clumped distribution. Researchers from the Arctic Ocean Diversity (ARCOD) project have documented rising numbers of warm-water crustaceans in the seas around Norway's Svalbard Islands. ARCOD is part of the Census of Marine Life, a huge 10-year project involving researchers in more than 80 nations that aims to chart
5103-566: The grid size used can have an effect on the output of these species distribution models. The standard 50x50 km grid size can select up to 2.89 times more area than when modeled with a 1x1 km grid for the same species. This has several effects on the species conservation planning under climate change predictions (global climate models, which are frequently used in the creation of species distribution models, usually consist of 50–100 km size grids) which could lead to over-prediction of future ranges in species distribution modeling. This can result in
5184-507: The largest distributors due to the current trends in globalization and the expanse of the transportation industry. For example, large tankers often fill their ballasts with water at one port and empty them in another, causing a wider distribution of aquatic species. On large scales, the pattern of distribution among individuals in a population is clumped. One common example of bird species' ranges are land mass areas bordering water bodies, such as oceans, rivers, or lakes; they are called
5265-463: The likelihood a species will occupy a given area are more preferred because these models include an estimate of confidence in the likelihood of the species being present/absent. They are also more valuable than data collected based on simple presence or absence because models based on probability allow the formation of spatial maps that indicates how likely a species is to be found in a particular area. Similar areas can then be compared to see how likely it
5346-505: The misidentification of protected areas intended for a species future habitat. The Species Distribution Grids Project is an effort led out of the University of Columbia to create maps and databases of the whereabouts of various animal species. This work is centered on preventing deforestation and prioritizing areas based on species richness. As of April 2009, data are available for global amphibian distributions, as well as birds and mammals in
5427-455: The population is evenly dispersed. Lastly, if R is significantly less than 1, the population is clumped. Statistical tests (such as t-test, chi squared, etc.) can then be used to determine whether R is significantly different from 1. The variance/mean ratio method focuses mainly on determining whether a species fits a randomly spaced distribution, but can also be used as evidence for either an even or clumped distribution. To utilize
5508-496: The product of the different social environments of dogs. From a young age, humans may be among a dog's primary social contacts, an environment that presents different stimuli than would be found by wolves in the wild. Intruders may frequent the boundaries of a captive dog's territory, thus triggering the bark response as a warning. Dogs also live in densely populated urban areas, allowing for more opportunities for socialization. For example, kennelled dogs may have increased barking due to
5589-502: The space between individuals generally arises from competition for a resource such as moisture or nutrients, or as a result of direct social interactions between individuals within the population, such as territoriality. For example, penguins often exhibit uniform spacing by aggressively defending their territory among their neighbors. The burrows of great gerbils for example are also regularly distributed, which can be seen on satellite images. Plants also exhibit uniform distributions, like
5670-429: The spring and summer months and females bear almost all the responsibility for raising them. Mothers of some species fast and nurse their young for a relatively short period of time while others take foraging trips at sea between nursing bouts. Walruses are known to nurse their young while at sea. Seals produce a number of vocalizations , notably the barks of California sea lions , the gong -like calls of walruses and
5751-402: The superfamily Phocoidea. There are 34 extant species of pinnipeds, and more than 50 fossil species of pinnipedimorphs. Otariids are also known as eared seals due to their pinnae . These animals swim mainly using their well-developed fore-flippers. They can also "walk" on land by shifting their hind-flippers forward under the body. The front end of an otariid's frontal bone protrudes between
5832-471: The tree species Leucaena leucocephala exudes a chemical that inhibits the growth of other plants but not those of its own species, and thus can affect the distribution of specific rival species. Allelopathy usually results in uniform distributions, and its potential to suppress weeds is being researched. Farming and agricultural practices often create uniform distribution in areas where it would not previously exist, for example, orange trees growing in rows on
5913-747: The upper and lower jaw. The familiar long upper tusks developed in the genera Valenictus and Odobenus . The lineage of the modern walrus may have spread from the North Pacific to the North Atlantic through the Caribbean and Central American Seaway 8–5 mya, and then back to the North Pacific via the Arctic 1 mya, or to the Arctic and subsequently the North Atlantic during the Pleistocene . Pinnipeds have streamlined, spindle-shaped bodies with small or non-existent ear flaps, rounded heads, short muzzles, flexible necks, limbs modified into flippers and small tails. The mammary glands and genitals can withdraw into
5994-418: The vegetation around them can suffer, especially if animals target one plant in particular. Clumped distribution in species acts as a mechanism against predation as well as an efficient mechanism to trap or corner prey. African wild dogs, Lycaon pictus , use the technique of communal hunting to increase their success rate at catching prey. Studies have shown that larger packs of African wild dogs tend to have
6075-442: The walrus relies on its hind limbs for locomotion, while its forelimbs are used for steering. Also, it has no outer ears. The epipterygoid of the jaw is well developed and the back of the nasal bones are horizontal. In the feet, the calcaneuses protrude in the middle. Phocids are known as true or "earless" seals. These animals lack outer ears and cannot position their hind-flippers to move on land, making them more cumbersome. This
6156-704: The water as dolphins , seals are more flexible and agile. Otariids primarily use their front limbs to propel themselves through the water, while phocids and walruses primarily use their hind limbs for this purpose. Otariids and walruses have hind limbs that can be pulled under the body and used as legs on land. By comparison, terrestrial locomotion by phocids is more cumbersome. Otariids have visible external ears, while phocids and walruses lack these. Pinnipeds have well-developed senses—their eyesight and hearing are adapted for both air and water, and they have an advanced tactile system in their whiskers or vibrissae. Some species are well adapted for diving to great depths. They have
6237-520: The world. In 1989, Annalisa Berta and colleagues proposed the unranked clade Pinnipedimorpha to contain the fossil genus Enaliarctos and modern seals as a sister group . Pinnipeds belong to the order Carnivora and the suborder Caniformia (known as dog-like carnivorans). Of the three extant families, the Otariidae and Odobenidae are grouped in the superfamily Otarioidea, while the Phocidae belong to
6318-429: The year animals tend to "clump" together around these crucial resources. Individuals might be clustered together in an area due to social factors such as selfish herds and family groups. Organisms that usually serve as prey form clumped distributions in areas where they can hide and detect predators easily. Other causes of clumped distributions are the inability of offspring to independently move from their habitat. This
6399-553: Was bred in New Zealand , and is bred based on ability rather than appearance or lineage. Compared to most domestic dogs, the bark of a dingo is short and monosyllabic. During observations, the Australian dingo's bark has a small variability; sub-groups of bark types, common among domestic dogs, could not be found. Furthermore, just 5% of the observed vocalizations consisted of barking. Australian dingoes bark only in swooshing noises or
6480-489: Was likely more of a fore-flipper swimmer, but could probably swim with either pair. One species, Enaliarctos emlongi , exhibited notable sexual dimorphism , suggesting that this physical characteristic may have been an important driver of pinniped evolution. A closer relative of extant pinnipeds was Pteronarctos , which lived in Oregon 19–15 mya. As in modern seals, the maxilla or upper jaw bone of Pteroarctos intersects with
6561-526: Was the first to recognize the pinnipeds as a distinct taxonomic unit; in 1811 he gave the name Pinnipedia to both a family and an order . American zoologist Joel Asaph Allen reviewed the world's pinnipeds in an 1880 monograph , History of North American pinnipeds, a monograph of the walruses, sea-lions, sea-bears and seals of North America . In this publication, he traced the history of names, gave keys to families and genera, described North American species and provided synopses of species in other parts of
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