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 7.77 million animal species on Earth. Animal body lengths range from 8.5 μm (0.00033 in) to 33.6 m (110 ft). 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.
Entries here consist of
Good and
Featured articles, which meet a core set of high editorial standards.
The European hare (Lepus europaeus), also known as the brown hare, is a
species of
hare native to
Europe and parts of
Asia. It is among the largest hare species and is adapted to temperate, open country. Hares are
herbivorous and feed mainly on grasses and herbs, supplementing these with twigs, buds, bark and field crops, particularly in winter. Their natural
predators include large
birds of prey,
canids and
felids. They rely on high-speed endurance running to escape predation, having long, powerful limbs and large nostrils.
Generally nocturnal and shy in nature, hares change their behaviour in the spring, when they can be seen in broad daylight chasing one another around in fields. During this spring frenzy, they sometimes strike one another with their paws ("boxing"). This is not just competition between males, but also a female hitting a male, either to show she is not yet ready to mate or to test his determination. The female nests in a depression on the surface of the ground rather than in a
burrow and the young are active as soon as they are born. Litters may consist of three or four young and a female can bear three litters a year, with hares living for up to twelve years. The breeding season lasts from January to August. (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 (1⁄64 in) 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...)
The Common Brushtail Possum (Trichosurus vulpecula) is the largest
possum species and is perhaps the most widespread
mammal in Australia. It grows to about 32–58 cm (13–23 in) in length, with an additional 24–40 cm (9–16 in) for its
prehensile tail (seen here hanging below the branch). It is mainly a
folivore, but has been known to eat small mammals such as rats. It is common in cities, having adapted well to human habitation.
The coconut octopus (Amphioctopus marginatus) is a medium-sized
cephalopod found in tropical waters of the western Pacific Ocean. It commonly preys upon
shrimp,
crabs, and
clams, and displays unusual behaviour, including bipedal walking and gathering and using
coconut shells and seashells for shelter.
Brittle stars, serpent stars, or ophiuroids (from
Latin ophiurus 'brittle star'; from
Ancient Greekὄφις (óphis) 'serpent', and οὐρά (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 60 cm (24 in) in length on the largest specimens. (Full article...)
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.
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.
A female Calliope Hummingbird (Stellula calliope), the smallest bird found in Canada and the United States, feeding insects to chicks. Found mostly in western North America (although
vagrants have been found in New York and Connecticut), it is
migratory and winters in southwestern Mexico.
A lateral (left side) anatomical diagram of an adult-stage nematode
hermaphroditeCaenorhabditis elegans (full size) with emphasis on the digestive and reproductive systems. C. elegans is a free-living, transparent
nematode (roundworm) which measures about 1 millimetre (0.039 in) in length. The hermaphrodite form, as seen here, is the most common, although a male form is also found. When self-inseminated, the species will lay about 300 eggs, but when the hermaphrodite is inseminated by a male, the number of progeny can exceed 1,000.
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 (40 ft) 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.
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...)
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.
Glaucus atlanticus is a species of small, blue
sea slug. This
pelagic aeolid
nudibranch floats upside down, using the surface tension of the water to stay up, and is carried along by the winds and ocean currents. The blue side of their body faces upwards, blending in with the blue of the water, while the grey side faces downwards, blending in with the silvery surface of the sea. G. atlanticus feeds on other pelagic creatures, including the
Portuguese man o' war.
The maxima clam (Tridacna maxima) is a species of
bivalve found throughout the
Indo-Pacific. It is found on the surface of reefs or sand, or partly embedded in coral (as with this specimen), in the oceans surrounding east Africa, India, China, Australia, Southeast Asia and the islands of the Pacific. This clam is much sought after in the aquarium trade, as its often striking coloration—the result of crystalline pigment—mimics that of the true
giant clam.
Entries here consist of
Good and
Featured articles, which meet a core set of high editorial standards.
Camouflage is the concealment of animals or objects of military interest by any combination of methods that helps them to remain unnoticed. This includes the use of high-contrast
disruptive patterns as used on
military uniforms, but anything that delays recognition can be used as camouflage. Camouflage involves deception, whether by looking like the background or by resembling something else, which may be plainly visible to observers. This article lists methods used by animals and the military to escape notice. (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 1The bilaterian gut develops in two ways. In many
protostomes, the blastopore develops into the mouth, while in
deuterostomes it becomes the anus. (from Animal)
Image 2A clade representation of seven dog breeds in relation to wolves. (from Zoology)
Image 10Linnaeus's table of the animal kingdom from the first edition of Systema Naturae (1735) (from Zoology)
Image 11A
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 13The microscopic cave snail Zospeum tholussum, found at depths of 743 to 1,392 m (2,438 to 4,567 ft) in the
Lukina Jama–Trojama cave system of
Croatia, is completely blind with a translucent shell (from Fauna)
Image 14A
gun dog retrieving a duck during a hunt (from Animal)
Image 37Idealised
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 44Bright coloration of orange elephant ear sponge, Agelas clathrodes signals its bitter taste to predators (from Animal coloration)
Image 45Squid chromatophores appear as black, brown, reddish and pink areas in this micrograph. (from Animal coloration)
Image 46Animals are unique in having the ball of cells of the early
embryo (1) develop into a hollow ball or
blastula (2). (from Animal)
Image 47A 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 48The black and yellow warning colours of the cinnabar moth caterpillar, Tyria jacobaeae, are avoided by some birds. (from Animal coloration)
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][a]
^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.
^
abcdNicol, David (June 1969). "The Number of Living Species of Molluscs". Systematic Zoology. 18 (2): 251–254.
doi:
10.2307/2412618.
JSTOR2412618.
^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.
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 7.77 million animal species on Earth. Animal body lengths range from 8.5 μm (0.00033 in) to 33.6 m (110 ft). 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.
Entries here consist of
Good and
Featured articles, which meet a core set of high editorial standards.
The European hare (Lepus europaeus), also known as the brown hare, is a
species of
hare native to
Europe and parts of
Asia. It is among the largest hare species and is adapted to temperate, open country. Hares are
herbivorous and feed mainly on grasses and herbs, supplementing these with twigs, buds, bark and field crops, particularly in winter. Their natural
predators include large
birds of prey,
canids and
felids. They rely on high-speed endurance running to escape predation, having long, powerful limbs and large nostrils.
Generally nocturnal and shy in nature, hares change their behaviour in the spring, when they can be seen in broad daylight chasing one another around in fields. During this spring frenzy, they sometimes strike one another with their paws ("boxing"). This is not just competition between males, but also a female hitting a male, either to show she is not yet ready to mate or to test his determination. The female nests in a depression on the surface of the ground rather than in a
burrow and the young are active as soon as they are born. Litters may consist of three or four young and a female can bear three litters a year, with hares living for up to twelve years. The breeding season lasts from January to August. (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 (1⁄64 in) 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...)
The Common Brushtail Possum (Trichosurus vulpecula) is the largest
possum species and is perhaps the most widespread
mammal in Australia. It grows to about 32–58 cm (13–23 in) in length, with an additional 24–40 cm (9–16 in) for its
prehensile tail (seen here hanging below the branch). It is mainly a
folivore, but has been known to eat small mammals such as rats. It is common in cities, having adapted well to human habitation.
The coconut octopus (Amphioctopus marginatus) is a medium-sized
cephalopod found in tropical waters of the western Pacific Ocean. It commonly preys upon
shrimp,
crabs, and
clams, and displays unusual behaviour, including bipedal walking and gathering and using
coconut shells and seashells for shelter.
Brittle stars, serpent stars, or ophiuroids (from
Latin ophiurus 'brittle star'; from
Ancient Greekὄφις (óphis) 'serpent', and οὐρά (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 60 cm (24 in) in length on the largest specimens. (Full article...)
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.
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.
A female Calliope Hummingbird (Stellula calliope), the smallest bird found in Canada and the United States, feeding insects to chicks. Found mostly in western North America (although
vagrants have been found in New York and Connecticut), it is
migratory and winters in southwestern Mexico.
A lateral (left side) anatomical diagram of an adult-stage nematode
hermaphroditeCaenorhabditis elegans (full size) with emphasis on the digestive and reproductive systems. C. elegans is a free-living, transparent
nematode (roundworm) which measures about 1 millimetre (0.039 in) in length. The hermaphrodite form, as seen here, is the most common, although a male form is also found. When self-inseminated, the species will lay about 300 eggs, but when the hermaphrodite is inseminated by a male, the number of progeny can exceed 1,000.
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 (40 ft) 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.
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...)
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.
Glaucus atlanticus is a species of small, blue
sea slug. This
pelagic aeolid
nudibranch floats upside down, using the surface tension of the water to stay up, and is carried along by the winds and ocean currents. The blue side of their body faces upwards, blending in with the blue of the water, while the grey side faces downwards, blending in with the silvery surface of the sea. G. atlanticus feeds on other pelagic creatures, including the
Portuguese man o' war.
The maxima clam (Tridacna maxima) is a species of
bivalve found throughout the
Indo-Pacific. It is found on the surface of reefs or sand, or partly embedded in coral (as with this specimen), in the oceans surrounding east Africa, India, China, Australia, Southeast Asia and the islands of the Pacific. This clam is much sought after in the aquarium trade, as its often striking coloration—the result of crystalline pigment—mimics that of the true
giant clam.
Entries here consist of
Good and
Featured articles, which meet a core set of high editorial standards.
Camouflage is the concealment of animals or objects of military interest by any combination of methods that helps them to remain unnoticed. This includes the use of high-contrast
disruptive patterns as used on
military uniforms, but anything that delays recognition can be used as camouflage. Camouflage involves deception, whether by looking like the background or by resembling something else, which may be plainly visible to observers. This article lists methods used by animals and the military to escape notice. (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 1The bilaterian gut develops in two ways. In many
protostomes, the blastopore develops into the mouth, while in
deuterostomes it becomes the anus. (from Animal)
Image 2A clade representation of seven dog breeds in relation to wolves. (from Zoology)
Image 10Linnaeus's table of the animal kingdom from the first edition of Systema Naturae (1735) (from Zoology)
Image 11A
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 13The microscopic cave snail Zospeum tholussum, found at depths of 743 to 1,392 m (2,438 to 4,567 ft) in the
Lukina Jama–Trojama cave system of
Croatia, is completely blind with a translucent shell (from Fauna)
Image 14A
gun dog retrieving a duck during a hunt (from Animal)
Image 37Idealised
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 44Bright coloration of orange elephant ear sponge, Agelas clathrodes signals its bitter taste to predators (from Animal coloration)
Image 45Squid chromatophores appear as black, brown, reddish and pink areas in this micrograph. (from Animal coloration)
Image 46Animals are unique in having the ball of cells of the early
embryo (1) develop into a hollow ball or
blastula (2). (from Animal)
Image 47A 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 48The black and yellow warning colours of the cinnabar moth caterpillar, Tyria jacobaeae, are avoided by some birds. (from Animal coloration)
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][a]
^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.
^
abcdNicol, David (June 1969). "The Number of Living Species of Molluscs". Systematic Zoology. 18 (2): 251–254.
doi:
10.2307/2412618.
JSTOR2412618.
^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.