The tail is the elongated section at the rear end of a bilaterian animal 's body; in general, the term refers to a distinct, flexible appendage extending backwards from the midline of the torso . In vertebrate animals that evolved to lose their tails (e.g. frogs and hominid primates ), the coccyx is the homologous vestigial of the tail. While tails are primarily considered a feature of vertebrates, some invertebrates such as scorpions and springtails , as well as snails and slugs , have tail-like appendages that are also referred to as tails.
41-959: Tail-shaped objects are sometimes referred to as "caudate" (e.g. caudate lobe , caudate nucleus ), and the body part associated with or proximal to the tail are given the adjective " caudal " (which is considered a more precise anatomical terminology ). Animal tails are used in a variety of ways. They provide a source of thrust for aquatic locomotion for fish , cetaceans and crocodilians and other forms of marine life . Terrestrial species of vertebrates that do not need to swim, e.g. cats and kangaroos , instead use their tails for balance ; and some, such as monkeys and opossums , have grasping prehensile tails , which are adapted for arboreal locomotion . Many animals use their tail for utility purposes, for example many grazing animals, such as horses and oxens , use their tails to drive away parasitic flies and sweep off other biting insects. Some animals with broad, furry tails (e.g. foxes ) often wrap
82-399: A fruiting tree, they will not associate with them otherwise and will not stay with other species for long. Fruit is eaten while perched and not in the air, and birds-of-paradise are able to use their feet as tools to manipulate and hold their food, allowing them to extract certain capsular fruit. There is some niche differentiation in fruit choice by species and any one species will only consume
123-450: A lure to attract prey , who may mistaken the tail as a worm . The extinct armored dinosaurs ( stegosaurs and ankylosaurs ) have tails with spikes or clubs as defensive weapons against predators. Tails are also used for communication and signalling . Most canines use their tails to communicate mood and intention. Some deer species flash the white underside of their tails to warn other nearby deer of possible danger, beavers slap
164-706: A species outside New Guinea is Phonygammus , one representative of which is found in the extreme north of Queensland . The remaining species are restricted to New Guinea and some of the surrounding islands. Many species have very small ranges, particularly those with restricted habitat types such as mid-montane forest (like the black sicklebill ) or island endemics (like the Wilson's bird-of-paradise ). The majority of birds-of-paradise live in tropical forests, including rainforests , swamps, and moss forests , nearly all of them solitary tree dwellers. Several species have been recorded in coastal mangroves. The southernmost species,
205-506: Is introduced (as Paradiseidae) in 1825 with Paradisaea as the type genus by the English naturalist William John Swainson . For many years the birds-of-paradise were treated as being closely related to the bowerbirds . Today while both are treated as being part of the Australasian lineage Corvida , the two are now thought to be only distantly related. The closest evolutionary relatives of
246-458: Is named after the tail-shaped hepatic tissue ( cauda ; Latin, "tail") papillary process of the liver, which arise from its left side. It also has a caudate process (that is not tail-like shaped) arising from its right side, which provides surface continuity between the caudate lobe and the visceral surface of the anatomical right lobe of the liver. The caudate process is a small elevation of the hepatic substance extending obliquely and laterally, from
287-428: Is situated behind the porta , and separates the fossa for the gall-bladder from the commencement of the fossa for the inferior vena cava . See Adriaan van den Spiegel 1578-1625 Spiegel's lobe. Budd–Chiari syndrome , caused by occlusion of hepatic venous outflow, can lead to hypertrophy of the caudate lobe due to its own caval anastomosis that allows for continued function of this lobe of the liver. The caudate lobe
328-427: Is six times the size of the left lobe. It occupies the right hypochondrium , on its posterior surface by the ligamentum venosum for the cranial (upper) half and by the ligamentum teres hepatis ( round ligament of liver ) for the caudal (under) half. The ligamentum teres hepatis turns around the inferior margin of the liver to come out ventral in the falciform ligament . The right lobe is functionally separated from
369-561: Is the large island of New Guinea ; all but two genera are found in New Guinea. Those other two are the monotypic genera Lycocorax and Semioptera , both of which are endemic to the Maluku Islands , to the west of New Guinea. Of the riflebirds in the genus Ptiloris , two are endemic to the coastal forests of eastern Australia , one occurs in both Australia and New Guinea, and one is only found in New Guinea. The only other genus to have
410-646: Is through short hepatic veins that drain directly into the inferior vena cava (IVC) due to its proximity to the IVC. [REDACTED] This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918) Birds of paradise 17 genera, 45 species The birds-of-paradise are members of the family Paradisaeidae of the order Passeriformes . The majority of species are found in eastern Indonesia , Papua New Guinea , and eastern Australia . The family has 45 species in 17 genera . The members of this family are perhaps best known for
451-474: The Couinaud system . These are also known as hepatic segments that are surgically resectable . The '' left lobe'' is smaller and more flattened than the right. It is situated in the epigastric , and left hypochondriac regions of the abdomen . Its upper surface is slightly convex and is moulded on to the diaphragm; its under surface presents the gastric impression and omental tuberosity . The right lobe
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#1732845020282492-556: The Epimachus sicklebills, Paradigalla, and the astrapias. The final clade includes the Cicinnurus and the Paradisaea birds-of-paradise. The exact limits of the family have been the subject of revision as well. The three species of satinbird (the genera Cnemophilus and Loboparadisea ) were treated as a subfamily of the birds-of-paradise, Cnemophilinae. In spite of differences in
533-400: The corvids . Birds-of-paradise range in size from the king bird-of-paradise at 50 g (1.8 oz) and 15 cm (5.9 in) to the curl-crested manucode at 44 cm (17 in) and 430 g (15 oz). The male black sicklebill , with its long tail, is the longest species at 110 cm (43 in). In most species, the tails of the males are larger and longer than those of
574-427: The liver is divided grossly into four parts or lobes : the right lobe , the left lobe , the caudate lobe , and the quadrate lobe . Seen from the front – the diaphragmatic surface – the liver is divided into two lobes: the right lobe and the left lobe. Viewed from the underside – the visceral surface – the other two smaller lobes, the caudate lobe and the quadrate lobe, are also visible. The two smaller lobes,
615-425: The paradise riflebird of Australia , lives in sub-tropical and temperate wet forests. As a group the manucodes are the most plastic in their habitat requirements; in particular, the glossy-mantled manucode , which inhabits both forest and open savanna woodland. Mid-montane habitats are the most commonly occupied habitat, with thirty of the forty species occurring in the 1000–2000 m altitudinal band. The diet of
656-566: The plumage of the males of the species, the majority of which are sexually dimorphic . The males of these species tend to have very long, elaborate feathers extending from the beak, wings, tail, or head. For the most part, they are confined to dense rainforest habitats. The diet of all species is dominated by fruit and to a lesser extent arthropods . The birds-of-paradise have a variety of breeding systems, ranging from monogamy to lek -type polygamy . A number of species are threatened by hunting and habitat loss . The family Paradisaeidae
697-467: The porta hepatis , also known as the transverse fissure of the liver , divides this left portion into four segments, which can be numbered in Roman numerals starting at the caudate lobe as I in an anticlockwise manner. From this parietal view , seven segments can be seen, because the eighth segment is only visible in the visceral view. The lobes of the liver are further divided into eight liver segments in
738-416: The vena cava and all the way forward to divide the liver and gallbladder into two halves. This line is called Cantlie's line and is used to mark the division between the two lobes. Other anatomical landmarks exist, such as the ligamentum venosum and the round ligament of the liver (ligamentum teres), which further divide the left side of the liver in two sections. An important anatomical landmark,
779-597: The animal to escape from a predator. Most birds' tails end in long feathers called rectrices . These feathers are used as a rudder, helping the bird steer and maneuver in flight ; they also help the bird to balance while it is perched. In some species—such as birds of paradise , lyrebirds , and most notably peafowl —modified tail feathers play an important role in courtship displays . The extra-stiff tail feathers of other species, including woodpeckers and woodcreepers , allow them to brace themselves firmly against tree trunks. In humans, tail bud refers to
820-472: The birds-of-paradise are the crow and jay family Corvidae , the monarch flycatchers Monarchidae , and the Australian mudnesters Struthideidae . A 2009 study examining the mitochondrial DNA of all species to examine the relationships within the family and to its nearest relatives estimated that the family emerged 24 million years ago, earlier than previous estimates. The study identified five clades within
861-403: The birds-of-paradise is dominated by fruit and arthropods, although small amounts of nectar and small vertebrates may also be taken. The ratio of the two food types varies by species, with fruit predominating in some species, and arthropods dominating the diet in others. The ratio of the two will affect other aspects of the behaviour of the species; for example, frugivorous species tend to feed in
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#1732845020282902-523: The caudal vertebrae, a result of atavism . In 2024, scientists claimed to have found a genetic mutation that contributed to the loss of the tail in the common ancestor of humans and other apes. Humans have a "tail bone" (the coccyx ) attached to the pelvis; it comprises fused vertebrae , usually four, at the bottom of the vertebral column . It does not normally protrude externally - humans are an acaudal (or acaudate ) species (i.e., tailless). Lobes of liver#Caudate lobe In human anatomy ,
943-401: The caudate lobe and the quadrate lobe, are known as superficial or accessory lobes, and both are located on the underside of the right lobe. The falciform ligament , visible on the front of the liver, makes a superficial division of the right and left lobes of the liver. From the underside, the two additional lobes are located on the right lobe. A line can be imagined running from the left of
984-726: The described species were so rare, he examined many controversial specimens and, during the 1920s and 1930s, published several papers on his hypothesis. Many of the species described in the late 19th and early 20th centuries are now generally considered to be hybrids, though some are still subject to dispute; their status is not likely to be settled definitely without genetic examination of museum specimens, which will come soon in summer 2021 in North America, South America, Africa, Europe, Asia, and Australia, and some birds in an aviary in Central Park Zoo . Birds-of-paradise are closely related to
1025-465: The dimorphic species is typically drab to blend in with their habitat, unlike the bright attractive colours found on the males. Younger males of these species have female-like plumage, and sexual maturity takes a long time, with the full adult plumage not being obtained for up to seven years. This affords the younger males protection from predators of more subdued colours and also reduces hostility from adult males. The centre of bird-of-paradise diversity
1066-1630: The family has been determined by Martin Irestedt and collaborators. Lycocorax – paradise-crows (2 species) Phonygammus – trumpet manucode Manucodia – manucodes (5 species) Pteridophora – King of Saxony bird-of-paradise Parotia – parotias (6 species) Seleucidis – twelve-wired bird-of-paradise Drepanornis – sicklebills (2 species) Semioptera – standardwing bird-of-paradise Lophorina – lophorinas (3 species) Ptiloris – riflebirds (4 species) Epimachus – sicklebills (2 species) Paradigalla – paradigallas (2 species) Astrapia – astrapias (5 species) Cicinnurus – King bird-of-paradise Diphyllodes – birds-of-paradise (2 species) Paradisornis – blue bird-of-paradise Paradisaea – birds-of-paradise (6 species) genus : Lycocorax genus : Manucodia genus : Phonygammus genus : Paradigalla genus : Astrapia genus : Parotia genus : Pteridophora genus : Lophorina genus : Ptiloris genus : Epimachus genus : Drepanornis genus : Cicinnurus genus : Diphyllodes genus : Semioptera genus : Seleucidis genus : Paradisaea Hybrid birds-of-paradise may occur when individuals of different species, that look similar and have overlapping ranges, confuse each other for their own species and crossbreed. When Erwin Stresemann realised that hybridisation among birds-of-paradise might be an explanation as to why so many of
1107-588: The family, and placed the split between the first clade, which contains the monogamous manucodes and paradise-crow , and all the other birds-of-paradise, to be 10 million years ago. The second clade includes the parotias and the King of Saxony bird-of-paradise . The third clade provisionally contains several genera, including Seleucidis , the Drepanornis sicklebills, Semioptera , Ptiloris, and Lophorina , although some of these are questionable. The fourth clade includes
1148-469: The females have larger bills than the males are more common, particularly in the insect-eating species. Plumage variation between the sexes is closely related to the breeding system. The manucodes and paradise-crow, which are socially monogamous, are sexually monomorphic . So are the two species of Paradigalla , which are polygamous. All these species have generally black plumage with varying amounts of green and blue iridescence . The female plumage of
1189-475: The females, the differences ranging from slight to extreme. The wings are rounded and in some species structurally modified on the males in order to make sound. There is considerable variation in the family with regard to bill shape. Bills may be long and decurved, as in the sicklebills and riflebirds, or small and slim like the Astrapias . As with body size, bill size varies between the sexes, although species where
1230-513: The forest canopy, whereas insectivores may feed lower down in the middle storey. Frugivores are more social than the insectivores, which are more solitary and territorial . Even the birds-of-paradise that are primarily insect eaters will still take large amounts of fruit. The family is overall an important seed disperser for the forests of New Guinea, as they do not digest the seeds. Species that feed on fruit will range widely searching for fruit, and while they may join other fruit-eating species at
1271-420: The fossa for the gall-bladder and the fossae for the inferior vena cava . These separate the right lobe into two smaller lobes on its left posterior part: the quadrate lobe and the caudate lobe. The quadrate lobe is an area of the liver situated on the undersurface of the medial segment left lobe (Couinaud segment IVb), bounded in front by the anterior margin of the liver, behind by the porta hepatis , on
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1312-436: The genus Melampitta , also from New Guinea, have been linked with the birds-of-paradise, but their relationships remain uncertain, more recently being linked with the Australian mudnesters. The silktail of Fiji has been linked with the birds-of-paradise many times since its discovery, but never formally assigned to the family. Recent molecular evidence now places the species with the fantails . A genus level phylogeny of
1353-399: The left lobe by the middle hepatic vein. From a functional perspective (one that takes the arterial, portal venous, and systemic venous anatomy into account) the falciform ligament separates the medial and lateral segments of the left hepatic lobe. The right lobe is of a somewhat quadrilateral form. Its under and posterior surfaces being marked by three fossæ: the fossa for the portal vein ,
1394-405: The liver is bounded below by the porta hepatis , on the right by the fossa for the inferior vena cava , and on the left by the fossa for the ductus venosus and the physiological division of the liver, called the ligamentum venosum . It looks backward, being nearly vertical in position; it is longer from above downward than from side to side, and is somewhat concave in the transverse direction. It
1435-410: The lower extremity of the caudate lobe to the undersurface of the right lobe. The caudate lobe has a complex blood supply system. It derives its arterial supply from the caudate arteries, which arise from the right, left, and middle hepatic arteries that are connected to each other. Besides, the caudate lobe also derives its supply from the right and left branches of the portal vein. Its venous drainage
1476-536: The mouth, foot morphology, and nesting habits they remained in the family until a 2000 study moved them to a separate family closer to the berrypeckers and longbills ( Melanocharitidae ). The same study found that the Macgregor's bird-of-paradise was actually a member of the large Australasian honeyeater family. In addition to these three species, a number of systematically enigmatic species and genera have been considered potential members of this family. The two species in
1517-451: The part of the embryo which develops into the end of the spine. However, this is not a tail. Infrequently, a child is born with a "soft tail", which contains no vertebrae, but only blood vessels , muscles , and nerves , but this is regarded as an abnormality rather than a vestigial true tail, even when such an appendage is located where the tail would be expected. Fewer than 40 cases have been reported of infants with "true tails" containing
1558-411: The right by the fossa for the gall-bladder , and on the left by the fossa for the umbilical vein . It is oblong in shape, its antero-posterior diameter being greater than its transverse. The caudate lobe ( posterior hepatic segment I ) is situated upon the posterosuperior surface of the liver on the right lobe of the liver, opposite the tenth and eleventh thoracic vertebrae . The caudate lobe of
1599-512: The tail around the body as means of thermal insulation like a blanket . Some species' tails serve aggressive functions, either predatorily or defensively . For example, the tails of scorpions have a stinger that contain venom , which can be used to either kill large prey or to fight off a threat. Similarly, stingrays have a thickened spine that can deliver penetrating trauma . Thresher sharks are known to use their long tails to stun prey. Many species of snakes wiggle their tails as
1640-533: The water with their tails to indicate danger, felids raise and quiver their tails while scent-marking , and canids (including domestic dogs ) indicate emotions through the positioning and movement of their tails. Rattlesnakes perform tail vibration to generate a distinct rattling noise that signals aggression and warns potential predators to stay away. Some species of lizard (e.g. geckos ) can self-amputate ("cast") their tails from their bodies to help them escape predators , which are either distracted by
1681-404: The wriggling detached tail or only manages to seize the severed tail while the lizard flees. Tails cast in this manner generally grow back over time, though the replacement is typically darker in colour than the original and contains only cartilage , not bone. Various species of rat demonstrate a similar function with their tails, known as degloving , in which the outer layer is shed in order for