Over 1.5 million living animal species have been described, of which around 1.05 million are insects, over 85,000 are molluscs, and around 65,000 are vertebrates. It has been estimated there are as many as 7.77million animal species on Earth. Animal body lengths range from 8.5μm (0.00033in) to 33.6m (110ft). They have complex ecologies and interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology, and the study of animal behaviors is known as ethology.
The thylacine (/ˈθaɪləsiːn/; binomial nameThylacinus cynocephalus), also commonly known as the Tasmanian tiger or Tasmanian wolf, is an extinct carnivorous marsupial that was native to the Australian mainland and the islands of Tasmania and New Guinea. The thylacine died out in New Guinea and mainland Australia around 3,600–3,200 years ago, prior to the arrival of Europeans, possibly because of the introduction of the dingo, whose earliest record dates to around the same time, but which never reached Tasmania. Prior to European settlement, around 5,000 remained in the wild on Tasmania. Beginning in the nineteenth century, they were perceived as a threat to the livestock of farmers and bounty hunting was introduced. The last known of its species died in 1936 at Hobart Zoo in Tasmania. The thylacine is widespread in popular culture and is a cultural icon in Australia.
The thylacine was known as the Tasmanian tiger because of the dark transverse stripes that radiated from the top of its back, and it was called the Tasmanian wolf because it resembled a medium- to large-sized canid. The name thylacine is derived from thýlakos meaning "pouch" and ine meaning "pertaining to", and refers to the marsupial pouch. Both sexes had a pouch. The females used theirs for rearing young, and the males used theirs as a protective sheath, covering the external reproductive organs. The animal had a stiff tail and could open its jaws to an unusual extent. Recent studies and anecdotal evidence on its predatory behaviour suggest that the thylacine was a solitary ambush predator specialised in hunting small to medium-sized prey. Accounts suggest that in the wild, it fed on small birds and mammals. It was the only member of the genus Thylacinus and family Thylacinidae to have survived until modern times. Its closest living relatives are the other members of Dasyuromorphia including the Tasmanian devil, from which it is estimated to have split 42–36 million years ago. (Full article...)
The Peacock flounder (Bothus mancus) is a species of lefteye flounder found widely in relatively shallow waters in the Indo-Pacific. This photomontage shows four separate views of the same fish, each several minutes apart, starting from the top left. Over the course of the photos, the fish changes its colors to match its new surroundings, and then finally (bottom right) buries itself in the sand, leaving only the eyes protruding.
A caterpillar of Lymantria dispar dispar, also known as the gypsy moth. First described by Carl Linnaeus in 1758, the gypsy moth is found throughout Eurasia, where it is considered a pest. The larvae emerge from egg masses in the spring, and then are dispersed by the wind and begin feeding on leaves. They are initially diurnal, but become nocturnal after their fourth molting.
Velodona togata is the only species in the octopus genus Velodona; the genus and species names come from the large membranes that connect its arms. It was first described by Carl Chun in his book Die Cephalopoden (from which this illustration is taken) in 1915. A second subspecies was described by Guy Coburn Robson in 1924.
Plate 5 from Ernst Haeckel's Kunstformen der Natur, showing a variety of calcareous sponges, a class of about 400 marine sponges that are found mostly in shallow tropical waters worldwide. Calcareous sponges vary from radially symmetrical vase-shaped body types to colonies made up of a meshwork of thin tubes, or irregular massive forms. The skeleton has either a mesh or honeycomb structure.
The sperm whale is the largest toothed animal on Earth. The species was hunted extensively by humans throughout history, until protected by a worldwide moratorium on whaling starting in 1985–86.
The Atlantic spadefish is a species of marine fish endemic to the shallow waters off the coast of the southeastern United States and in the Caribbean Sea. They are similar in appearance to fresh waterangelfish, but much larger, reaching up to three feet (0.9 m) in length. Due to their reputation as strong fighters, they are popular game fish, especially during the summer months when they are most active.
Thysanozoon nigropapillosum, the yellow-spotted flatworm, is a species of marine flatworm in the family Pseudocerotidae. The species is native to the tropical Indo-Pacific region, where it lives in shallow reef habitats. Flatworms are hermaphrodites, each being able to act as either male or female. As a donor of sperm, it can grip the margin of the recipient's body, using its two penises in a chopstick-like manner, and deposit sperm on the surface of the skin of the recipient, even while it is actively swimming.
This picture shows a yellow-spotted flatworm photographed in Manta Ray Bay, on the island of Yap in the Federated States of Micronesia. The flatworm is seen swimming to the right at a depth of 12 metres (40ft) by undulating the margins of its body. The pseudotentacles at the front have simple eyes and sensory receptors to enable the flatworm to find tunicates on which it feeds.
Liguus virgineus, also known as the candy cane snail, is a species of snail in the family Orthalicidae. It is native to the Caribbean island of Hispaniola, in the nations of Haiti and the Dominican Republic. There have also been at least three reports of living specimens being found in the Florida Keys of the United States. The snail lives on trees and feeds on moss, fungi and microscopic algae covering the bark.
Brittle stars, serpent stars, or ophiuroids (fromLatin ophiurus'brittle star'; fromAncient Greekὄφις (óphis)'serpent',andοὐρά (ourá)'tail'; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomotion. The ophiuroids generally have five long, slender, whip-like arms which may reach up to 60cm (24in) in length on the largest specimens. (Full article...)
A macro view of a Gonia capitatafly feeding on honey, showing its proboscis and pedipalps (the two appendages protruding from the proboscis), two types of insect mouthparts. The proboscis actually comprises the labium, a quadrupedal structure, and a sponge-like labellum at the end. Flies eat solid food by secreting saliva and dabbing it over the food item. As the saliva dissolves the food, the solution is then drawn up into the mouth as a liquid. The labellum's surface is covered by minute food channels which form a tube leading to the esophagus, and food is drawn up the channels by capillary action.
The Osprey (Pandion haliaetus) is a medium large raptor which is a specialist fish-eater with a worldwide distribution. It is often known by other colloquial names such as Fish Hawk, Sea Hawk or Fish Eagle.
The Osprey is particularly well adapted to its diet, with reversible outer toes, closable nostrils to keep out water during dives, and backwards facing scales on the talons which act as barbs to help catch fish.
The leopard shark (Triakis semifasciata) is a species of hound shark found along the Pacific coast of North America from the U.S. state of Oregon to Mazatlán in Mexico. Typically measuring 1.2–1.5 m (3.9–4.9 ft) long, this slender-bodied shark is characterized by black saddle-like markings and large spots over its back.
The flatworms, flat worms, Platyhelminthes, or platyhelminths (from the Greek πλατύ, platy, meaning "flat" and ἕλμινς (root: ἑλμινθ-), helminth-, meaning "worm") are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates. Being acoelomates (having no body cavity), and having no specialised circulatory and respiratoryorgans, they are restricted to having flattened shapes that allow oxygen and nutrients to pass through their bodies by diffusion. The digestive cavity has only one opening for both ingestion (intake of nutrients) and egestion (removal of undigested wastes); as a result, the food can not be processed continuously. (Full article...)
Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquaticinvertebrate animals, nearly all living in sedentary colonies. Typically about 0.5 millimetres (1⁄64in) long, they have a special feeding structure called a lophophore, a "crown" of tentacles used for filter feeding. Most marine bryozoans live in tropical waters, but a few are found in oceanic trenches and polar waters. The bryozoans are classified as the marine bryozoans (Stenolaemata), freshwater bryozoans (Phylactolaemata), and mostly-marine bryozoans (Gymnolaemata), a few members of which prefer brackish water. 5,869living species are known. Originally all of the crown group Bryozoa were colonial, but as an adaptation to a mesopsammal (interstitial spaces in marine sand) life or to deep‐sea habitats, secondarily solitary forms have since evolved. Solitary species has been described in four genera; Aethozooides, Aethozoon, Franzenella and Monobryozoon). The latter having a statocyst‐like organ with a supposed excretory function. (Full article...)
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Mustelidae is a family of mammals in the orderCarnivora, which includes weasels, badgers, otters, ferrets, martens, minks, and wolverines, and many other extant and extinctgenera. A member of this family is called a mustelid; Mustelidae is the largest family in Carnivora, and its extant species are divided into eight subfamilies. They are found on all continents except Antarctica and Australia, and are a diverse family; sizes range, including tails, from the widespread 17cm (7in) least weasel to the 1.8-meter (6ft) giant otter of Amazonian South America. Habitats vary widely as well, from the arborealmarten to the fossorialEuropean badger to the marinesea otter. Population sizes are largely unknown, though two species, the sea mink and Japanese otter, were hunted to extinction in 1894 and 1979, respectively, and several other species are endangered. Some species have been domesticated, e.g. the ferret and some populations of the South American tayra. Mustelidae is one of the oldest families in Carnivora; early mustelids first appeared around 28–33 million years ago.
The 23 genera and 63 extant species of Mustelidae are split into 8 subfamilies: Guloninae, martens and wolverines; Helictidinae, ferret-badgers; Ictonychinae, African polecats and grisons; Lutrinae, otters; Melinae, Eurasian badgers; Mellivorinae, the honey badger; Mustelinae, weasels and minks; and Taxidiinae, the American badger. In addition to the extant subfamilies, Mustelidae includes three extinct subfamilies designated as Leptarctinae, Mustelavinae, and Oligobuninae. Extinct species have also been placed into all of the extant subfamilies besides Helictidinae, in both extant and extinct genera; around 200 extinct Mustelidae species have been found, as well as fossil genera not given a species name, though due to ongoing research and discoveries the exact number and categorization is not fixed. (Full article...)
...that the Southern Giant Petrel is the leading predator to the Emperor Penguin, and may be responsible for up to 34% of chick deaths in some colonies?
...that some goats freeze for ten seconds whenever startled due to the genetic condition known as myotonia congenita, and have thus been dubbed "fainting goats"?
The following are images from various animal-related articles on Wikipedia.
Image 1Animals are unique in having the ball of cells of the early embryo (1) develop into a hollow ball or blastula (2). (from Animal)
Image 2A praying mantis in deimatic or threat pose displays conspicuous patches of colour to startle potential predators. This is not warning coloration as the insect is palatable. (from Animal coloration)
Image 7A brilliantly-coloured oriental sweetlips fish (Plectorhinchus vittatus) waits while two boldly-patterned cleaner wrasse (Labroides dimidiatus) pick parasites from its skin. The spotted tail and fin pattern of the sweetlips signals sexual maturity; the behaviour and pattern of the cleaner fish signal their availability for cleaning service, rather than as prey (from Animal coloration)
Image 8A gun dog retrieving a duck during a hunt (from Animal)
Image 9Animal anatomical engraving from Handbuch der Anatomie der Tiere für Künstler. (from Zoology)
Image 29The microscopic cave snail Zospeumtholussum, found at depths of 743 to 1,392m (2,438 to 4,567ft) in the Lukina Jama–Trojama cave system of Croatia, is completely blind with a translucent shell (from Fauna)
Image 30A clade representation of seven dog breeds in relation to wolves. (from Zoology)
Image 31Simplified schematic of an island's fauna – all its animal species, highlighted in boxes (from Fauna)
Image 32Idealised bilaterian body plan. With an elongated body and a direction of movement the animal has head and tail ends. Sense organs and mouth form the basis of the head. Opposed circular and longitudinal muscles enable peristaltic motion. (from Animal)
Image 38The bilaterian gut develops in two ways. In many protostomes, the blastopore develops into the mouth, while in deuterostomes it becomes the anus. (from Animal)
The following table lists estimated numbers of described extant species for the animal groups with the largest numbers of species,[1] along with their principal habitats (terrestrial, fresh water,[2] and marine),[3] and free-living or parasitic ways of life.[4] Species estimates shown here are based on numbers described scientifically; much larger estimates have been calculated based on various means of prediction, and these can vary wildly. For instance, around 25,000–27,000 species of nematodes have been described, while published estimates of the total number of nematode species include 10,000–20,000; 500,000; 10 million; and 100 million.[5] Using patterns within the taxonomic hierarchy, the total number of animal species—including those not yet described—was calculated to be about 7.77 million in 2011.[6][7][lower-alpha 1]
The application of DNA barcoding to taxonomy further complicates this; a 2016 barcoding analysis estimated a total count of nearly 100,000 insect species for Canada alone, and extrapolated that the global insect fauna must be in excess of 10 million species, of which nearly 2 million are in a single fly family known as gall midges (Cecidomyiidae).[8]
Stork, Nigel E. (January 2018). "How Many Species of Insects and Other Terrestrial Arthropods Are There on Earth?". Annual Review of Entomology. 63 (1): 31–45. doi:10.1146/annurev-ento-020117-043348. PMID28938083. S2CID23755007. Stork notes that 1m insects have been named, making much larger predicted estimates.
Sluys, R. (1999). "Global diversity of land planarians (Platyhelminthes, Tricladida, Terricola): a new indicator-taxon in biodiversity and conservation studies". Biodiversity and Conservation. 8 (12): 1663–1681. doi:10.1023/A:1008994925673. S2CID38784755.
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