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Brain–body Mass Ratio
Brain–body mass ratio, also known as the brain–body weight ratio, is the ratio of brain mass to body mass, which is hypothesized to be a rough estimate of the intelligence of an animal, although fairly inaccurate in many cases. A more complex measurement, encephalization quotient, takes into account allometric effects of widely divergent body sizes across several taxa. The raw brain-to-body mass ratio is however simpler to come by, and is still a useful tool for comparing encephalization within species or between fairly closely related species. __TOC__ Brain–body size relationship Brain size usually increases with body size in animals (i.e. large animals usually have larger brains than smaller animals); the relationship is not, however, linear. Small mammals such as mice may have a brain/body ratio similar to humans, while elephants have a comparatively lower brain/body ratio. In animals, it is thought that the larger the brain, the more brain weight will be available ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monitor Lizard
Monitor lizards are lizards in the genus ''Varanus,'' the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and one species is also found in the Americas as an invasive species. About 80 species are recognized. Monitor lizards have long necks, powerful tails and claws, and well-developed limbs. The adult length of extant species ranges from in some species, to over in the case of the Komodo dragon, though the extinct varanid known as megalania (''Varanus priscus'') may have been capable of reaching lengths more than . Most monitor species are terrestrial, but arboreal and semiaquatic monitors are also known. While most monitor lizards are carnivorous, eating eggs, smaller reptiles, fish, birds, insects, and small mammals, some also eat fruit and vegetation, depending on where they live. Distribution The various species cover a vast area, occurring through Africa, the Indian subcontinent, to China, the Ryukyu Islands in sout ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manta Ray
Manta rays are large rays belonging to the genus '' Mobula'' (formerly its own genus ''Manta''). The larger species, '' M. birostris'', reaches in width, while the smaller, '' M. alfredi'', reaches . Both have triangular pectoral fins, horn-shaped cephalic fins and large, forward-facing mouths. They are classified among the Myliobatiformes ( stingrays and relatives) and are placed in the family Myliobatidae (eagle rays). They have the largest brains and brain to body ratio of all fish, and can pass the mirror test. Mantas are found in warm temperate, subtropical and tropical waters. Both species are pelagic; ''M. birostris'' migrates across open oceans, singly or in groups, while ''M. alfredi'' tends to be resident and coastal. They are filter feeders and eat large quantities of zooplankton, which they gather with their open mouths as they swim. However, research suggests that the majority of their diet (73%) actually comes from mesopelagic sources. Gestation lasts ove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthrop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shark
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the rays. However, the term "shark" has also been used to refer to all extinct members of Chondrichthyes with a shark-like morphology, such as hybodonts and xenacanths. The oldest modern sharks are known from the Early Jurassic. They range in size from the small dwarf lanternshark (''Etmopterus perryi''), a deep sea species that is only in length, to the whale shark (''Rhincodon typus''), the largest fish in the world, which reaches approximately in length. Sharks are found in all seas and are common to depths up to . They generally do not live in freshwater, although there are a few known exceptions, such as the bull shark and the river shark, which can be found in both seawater ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invertebrate
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate subphylum Vertebrata. Familiar examples of invertebrates include arthropods, mollusks, annelids, echinoderms and cnidarians. The majority of animal species are invertebrates; one estimate puts the figure at 97%. Many invertebrate taxa have a greater number and variety of species than the entire subphylum of Vertebrata. Invertebrates vary widely in size, from 50 μm (0.002 in) rotifers to the 9–10 m (30–33 ft) colossal squid. Some so-called invertebrates, such as the Tunicata and Cephalochordata, are more closely related to vertebrates than to other invertebrates. This makes the invertebrates paraphyletic, so the term has little meaning in taxonomy. Etymology The word "invertebrate" comes from the Latin word ''vertebra' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jumping Spider
Jumping spiders are a group of spiders that constitute the family Salticidae. As of 2019, this family contained over 600 described genera and over 6,000 described species, making it the largest family of spiders at 13% of all species. Jumping spiders have some of the best vision among arthropods and use it in courtship, hunting, and navigation. Although they normally move unobtrusively and fairly slowly, most species are capable of very agile jumps, notably when hunting, but sometimes in response to sudden threats or crossing long gaps. Both their book lungs and tracheal system are well-developed, and they use both systems (bimodal breathing). Jumping spiders are generally recognized by their eye pattern. All jumping spiders have four pairs of eyes, with the anterior median pair being particularly large. Distinguishing characteristics Jumping spiders are among the easiest to distinguish from similar spider families because of the shape of the cephalothorax and their eye patt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octopus
An octopus ( : octopuses or octopodes, see below for variants) is a soft-bodied, eight- limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, an octopus is bilaterally symmetric with two eyes and a beaked mouth at the center point of the eight limbs. The soft body can radically alter its shape, enabling octopuses to squeeze through small gaps. They trail their eight appendages behind them as they swim. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates. Octopuses inhabit various regions of the ocean, including coral reefs, pelagic waters, and the seabed; some live in the intertidal zone and others at abyssal depths. Most species grow quickly, mature earl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raven
A raven is any of several larger-bodied bird species of the genus ''Corvus''. These species do not form a single taxonomic group within the genus. There is no consistent distinction between "crows" and "ravens", common names which are assigned to different species chiefly on the basis of their size. The largest raven species are the common raven and the thick-billed raven. Etymology The term "raven" originally referred to the common raven (''Corvus corax''), the type species of the genus ''Corvus'', which has a larger distribution than any other species of ''Corvus'', ranging over much of the Northern Hemisphere. The modern English word ''raven'' has cognates in all other Germanic languages, including Old Norse (and subsequently modern Icelandic) and Old High German , all of which descend from Proto-Germanic . Collective nouns for a group of ravens (or at least the common raven) include "rave", "treachery", "unkindness" and "conspiracy". In practice, most people use the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magpie
Magpies are birds of the Corvidae family. Like other members of their family, they are widely considered to be intelligent creatures. The Eurasian magpie, for instance, is thought to rank among the world's most intelligent creatures, and is one of the few non-mammal species able to recognize itself in a mirror test. They are particularly well known for their songs and were once popular as cagebirds. In addition to other members of the genus '' Pica'', corvids considered as magpies are in the genera '' Cissa'', '' Urocissa'', and '' Cyanopica''. Magpies of the genus ''Pica'' are generally found in temperate regions of Europe, Asia, and western North America, with populations also present in Tibet and high-elevation areas of Kashmir. Magpies of the genus ''Cyanopica'' are found in East Asia and the Iberian Peninsula. The birds called magpies in Australia are, however, not related to the magpies in the rest of the world. Name References dating back to Old English call the bird ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crow
A crow is a bird of the genus ''Corvus'', or more broadly a synonym for all of ''Corvus''. Crows are generally black in colour. The word "crow" is used as part of the common name of many species. The related term " raven" is not pinned scientifically to any certain trait, but is rather a general grouping for larger ''Corvus spp.'' Species * ''Corvus albus'' – pied crow (Central African coasts to southern Africa) * ''Corvus bennetti'' – little crow (Australia) * ''Corvus brachyrhynchos'' – American crow (United States, southern Canada, northern Mexico) * ''Corvus capensis'' – Cape crow or Cape rook (Eastern and southern Africa) * ''Corvus cornix'' – hooded crow (Northern and Eastern Europe and Northern Africa and Middle East) * ''Corvus corone'' – carrion crow (Europe and eastern Asia) *''Corvus culminatus'' – Indian jungle crow (South Asia) * ''Corvus edithae'' – Somali crow or dwarf raven (eastern Africa) * ''Corvus enca'' – slender-billed crow (Malaysia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parrot
Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoidea ("true" parrots), the Cacatuoidea (cockatoos), and the Strigopoidea (New Zealand parrots). One-third of all parrot species are threatened by extinction, with higher aggregate extinction risk ( IUCN Red List Index) than any other comparable bird group. Parrots have a generally pantropical distribution with several species inhabiting temperate regions in the Southern Hemisphere, as well. The greatest diversity of parrots is in South America and Australasia. Characteristic features of parrots include a strong, curved bill, an upright stance, strong legs, and clawed zygodactyl feet. Many parrots are vividly coloured, and some are multi-coloured. Most parrots exhibit little or no sexual dimorphism in the visual spectrum. They form t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
