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CLAW Hypothesis Graphic 2 AYool
A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes (mammals, reptiles, birds). Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or tarsus for gripping a surface as they walk. The pincers of crabs, lobsters and scorpions, more formally known as their chelae, are sometimes called claws. A true claw is made of a hard protein called keratin. Claws are used to catch and hold prey in carnivorous mammals such as cats and dogs, but may also be used for such purposes as digging, climbing trees, self-defense and grooming, in those and other species. Similar appendages that are flat and do not come to a sharp point are called nails instead. Claw-like projections that do not form at the end of digits but spring from other parts of the foot are properly named spurs. Tetrapods In tetrapods, claws are made of keratin and consist of two layers. The unguis is the harder external layer, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cat Claw Closeup
The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of the family. Cats are commonly kept as house pets but can also be farm cats or feral cats; the feral cat ranges freely and avoids human contact. Domestic cats are valued by humans for companionship and their ability to kill rodents. About 60 cat breeds are recognized by various cat registries. The cat is similar in anatomy to the other felid species: they have a strong flexible body, quick reflexes, sharp teeth, and retractable claws adapted to killing small prey. Their night vision and sense of smell are well developed. Cat communication includes vocalizations like meowing, purring, trilling, hissing, growling, and grunting as well as cat-specific body language. Although the cat is a social species, they are a solitary hunter. As a pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dogs
The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. Dogs were the first species to be domesticated by hunter-gatherers over 15,000 years ago before the development of agriculture. Due to their long association with humans, dogs have expanded to a large number of domestic individuals and gained the ability to thrive on a starch-rich diet that would be inadequate for other canids. The dog has been selectively bred over millennia for various behaviors, sensory capabilities, and physical attributes. Dog breeds vary widely in shape, size, and color. They perform many roles for humans, such as hunting, herding, pulling loads, protection, assisting police and the military, companionship, therapy, and aiding disabled people. Over the millennia, dogs became uniquely adapted to human behavior, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dewclaw
A dewclaw is a digit – vestigial in some animals – on the foot of many mammals, birds, and reptiles (including some extinct orders, like certain theropods). It commonly grows higher on the leg than the rest of the foot, such that in digitigrade or unguligrade species it does not make contact with the ground when the animal is standing. The name refers to the dewclaw's alleged tendency to brush dew away from the grass.Danziger, D., & McCrum, M. (2008). ''The Thingummy: A book about those everyday objects you just can't name''. London: Doubleday. On dogs and cats the dewclaws are on the inside of the front legs, similarly to a human's thumb, which shares evolutionary homology. Although many animals have dewclaws, other similar species do not, such as horses, giraffes and the African wild dog. Dogs Dogs almost always have dewclaws on the inside of the front legs and occasionally also on the hind legs. Unlike front dewclaws, rear dewclaws tend to have little bone or muscle s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nimravidae
Nimravidae is an extinct family (biology), family of carnivorans, sometimes known as false saber-toothed cats, whose fossils are found in North America and Eurasia. Not considered to belong to the true cats (family Felidae), the nimravids are generally considered closely related and classified as a distinct family in the suborder Feliformia. Fossils have been dated from the Middle Eocene through the Late Miocene epochs (Bartonian through Tortonian stages, 40.4–7.2 million years ago), spanning about . The barbourofelids, which were formerly classified as a subfamily of the Nimravidae, were reassigned to their own distinct family Barbourofelidae in 2004. However, some recent studies suggest the barbourofelids are a branch of the nimravids, suggesting that this debate might not be settled yet. Morphology and evolution Most nimravids had muscular, low-slung, cat-like bodies, with shorter legs and tails than are typical of cats. Unlike extant taxon, extant Feliformia, the nimravids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viverridae
Viverridae is a family of small to medium-sized, feliform mammals. The viverrids () comprise 33 species placed in 14 genera. This family was named and first described by John Edward Gray in 1821. Viverrids occur all over Africa, southern Europe, and South and Southeast Asia, across the Wallace Line. Their occurrence in Sulawesi and in some of the adjoining islands shows them to be ancient inhabitants of the Old World tropics. Characteristics Viverrids have four or five toes on each foot and half-retractile claws. They have six incisors in each jaw and molars with two tubercular grinders behind in the upper jaw, and one in the lower jaw. The tongue is rough with sharp prickles. A pouch or gland occurs beneath the anus, but there is no cecum. Viverrids are the most primitive of all the families of feliform Carnivora and clearly less specialized than the Felidae. In external characteristics, they are distinguished from the Felidae by the longer muzzle and tuft of facial vibrissae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Felidae
Felidae () is the family of mammals in the order Carnivora colloquially referred to as cats, and constitutes a clade. A member of this family is also called a felid (). The term "cat" refers both to felids in general and specifically to the domestic cat (''Felis catus''). Felidae species exhibit the most diverse fur pattern of all terrestrial carnivores. Cats have retractile claws, slender muscular bodies and strong flexible forelimbs. Their teeth and facial muscles allow for a powerful bite. They are all obligate carnivores, and most are solitary predators ambushing or stalking their prey. Wild cats occur in Africa, Europe, Asia and the Americas. Some wild cat species are adapted to forest habitats, some to arid environments, and a few also to wetlands and mountainous terrain. Their activity patterns range from nocturnal and crepuscular to diurnal, depending on their preferred prey species. Reginald Innes Pocock divided the extant Felidae into three subfamilies: the P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protraction
Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relative to the anatomical position of the body parts involved. Anatomists and others use a unified set of terms to describe most of the movements, although other, more specialized terms are necessary for describing unique movements such as those of the hands, feet, and eyes. In general, motion is classified according to the anatomical plane it occurs in. ''Flexion'' and ''extension'' are examples of ''angular'' motions, in which two axes of a joint are brought closer together or moved further apart. ''Rotational'' motion may occur at other joints, for example the shoulder, and are described as ''internal'' or ''external''. Other terms, such as ''elevation'' and ''depression'', describe movement above or below the horizontal plane. Many anatomica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Predator
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the host) and parasitoidism (which always does, eventually). It is distinct from scavenging on dead prey, though many predators also scavenge; it overlaps with herbivory, as seed predators and destructive frugivores are predators. Predators may actively search for or pursue prey or wait for it, often concealed. When prey is detected, the predator assesses whether to attack it. This may involve ambush or pursuit predation, sometimes after stalking the prey. If the attack is successful, the predator kills the prey, removes any inedible parts like the shell or spines, and eats it. Predators are adapted and often highly specialized for hunting, with acute senses such as vision, hearing, or smell. Many predatory animals, both vertebrate and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phalanx Bones
The phalanges (singular: ''phalanx'' ) are digital bones in the hands and feet of most vertebrates. In primates, the thumbs and big toes have two phalanges while the other digits have three phalanges. The phalanges are classed as long bones. Structure The phalanges are the bones that make up the fingers of the hand and the toes of the foot. There are 56 phalanges in the human body, with fourteen on each hand and foot. Three phalanges are present on each finger and toe, with the exception of the thumb and large toe, which possess only two. The middle and far phalanges of the fifth toes are often fused together (symphalangism). The phalanges of the hand are commonly known as the finger bones. The phalanges of the foot differ from the hand in that they are often shorter and more compressed, especially in the proximal phalanges, those closest to the torso. A phalanx is named according to whether it is proximal, middle, or distal and its associated finger or toe. The proximal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnivora
Carnivora is a Clade, monophyletic order of Placentalia, placental mammals consisting of the most recent common ancestor of all felidae, cat-like and canidae, dog-like animals, and all descendants of that ancestor. Members of this group are formally referred to as carnivorans, and have evolved to specialize in eating flesh. The order is the fifth largest order of mammals, comprising at least 279 species. Carnivorans live on every major landmass and in a variety of habitats, ranging from the cold polar regions to the hyper-arid region of the Sahara Desert to the open seas. They come in a very large array of different body plans in contrasting shapes and sizes. Carnivora can be divided into two subclades: the cat-like Feliformia and the dog-like Caniformia, which are differentiated based on the structure of their ear bones and cranial features. The feliforms include families such as the felidae, cats, the hyenas, the mongooses and the viverridae, civets. The majority of felifor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrapod
Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct therapsids and all extant mammals). Tetrapods evolved from a clade of primitive semiaquatic animals known as the Tetrapodomorpha which, in turn, evolved from ancient lobe-finned fish (sarcopterygians) around 390 million years ago in the Middle Devonian period; their forms were transitional between lobe-finned fishes and true four-limbed tetrapods. Limbed vertebrates (tetrapods in the broad sense of the word) are first known from Middle Devonian trackways, and body fossils became common near the end of the Late Devonian but these were all aquatic. The first crown-tetrapods (last common ancestors of extant tetrapods capable of terrestrial locomotion) appeared by the very early Carboniferous, 350 million years ago. The specific aquatic ancestors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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