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Cephalic Index In Cats And Dogs
The cephalic index of a vertebrate is the ratio between the width (side to side) and length (front to back) of its cranium (skull). This ratio does not concern the muzzle or face, and thus is distinct from the ''craniofacial ratio'', which compares the size of the cranium to the length of the muzzle. The two measures are often confused in descriptions of dog breeds. The cephalic index is used to classify animals into three groups: Brachycephalic (literally 'short-headed'): the length of the cranium is shorter than the width, giving the top and sides of the cranium a round shape, often referred to as 'apple-head'. Image:Chihuahua 01 K.jpg Image:LakiJustbluein.jpg Mesaticephalic or mesocephalic ('middle-headed'): the length and width are equal, giving a square shape. When dealing with animals, especially dogs, the more appropriate and commonly used term is not "mesocephalic", but rather "mesaticephalic", which is a ratio of head to nasal cavity.Retrieved from http://medical-d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described. Vertebrates comprise such groups as the following: * jawless fish, which include hagfish and lampreys * jawed vertebrates, which include: ** cartilaginous fish (sharks, rays, and ratfish) ** bony vertebrates, which include: *** ray-fins (the majority of living bony fish) *** lobe-fins, which include: **** coelacanths and lungfish **** tetrapods (limbed vertebrates) Extant vertebrates range in size from the frog species ''Paedophryne amauensis'', at as little as , to the blue whale, at up to . Vertebrates make up less than five percent of all described animal species; the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cranium
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, these two parts are the neurocranium and the viscerocranium ( facial skeleton) that includes the mandible as its largest bone. The skull forms the anterior-most portion of the skeleton and is a product of cephalisation—housing the brain, and several sensory structures such as the eyes, ears, nose, and mouth. In humans these sensory structures are part of the facial skeleton. Functions of the skull include protection of the brain, fixing the distance between the eyes to allow stereoscopic vision, and fixing the position of the ears to enable sound localisation of the direction and distance of sounds. In some animals, such as horned ungulates (mammals with hooves), the skull also has a defensive function by providing the mount (on the fron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snout
A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, rostrum, or proboscis. The wet furless surface around the nostrils of the nose of many mammals is called the rhinarium (colloquially this is the "cold wet snout" of some mammals). The rhinarium is often associated with a stronger sense of olfaction. Variation Snouts are found on many mammals in a variety of shapes. Some animals, including ursines and great cats, have box-like snouts, while others, like shrews, have pointed snouts. Pig snouts are flat and cylindrical. Primates Strepsirrhine primates have muzzles, as do baboons. Great apes have reduced muzzles, with the exception being human beings, whose face does not have protruding jaws nor a snout but merely a human nose. Dogs The muzzle begins at the stop, just below the eyes, and includes the dog's nose and mouth. In the domestic dog, most of the upper muzzle contains organs for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dog Breed
A dog breed is a particular strain of dog that was purposefully bred by humans to perform specific tasks, such as herding, hunting, and guarding. Dogs are the most variable mammal on Earth, with artificial selection producing around 450 globally recognized breeds. These breeds possess distinct traits related to morphology, which include body size, skull shape, tail phenotype, fur type, body shape, and coat colour. Their behavioral traits include guarding, herding, and hunting, and personality traits such as hyper-social behavior, boldness, and aggression. Most breeds were derived from small numbers of founders within the last 200 years. As a result, today dogs are the most abundant carnivore species and are dispersed around the world. A dog breed will consistently produce the physical traits, movement and temperament that were developed over decades of selective breeding. For each breed they recognize, kennel clubs and breed registries usually maintain and publish a breed sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brachycephaly
Brachycephaly (derived from the Ancient Greek '' βραχύς'', 'short' and '' κεφαλή'', 'head') is the shape of a skull shorter than typical for its species. It is perceived as a desirable trait in some domesticated dog and cat breeds, notably the pug and Persian, and can be normal or abnormal in other animal species. In humans, the cephalic disorder is known as flat head syndrome, and results from premature fusion of the coronal sutures, or from external deformation. The coronal suture is the fibrous joint that unites the frontal bone with the two parietal bones of the skull. The parietal bones form the top and sides of the skull. This feature can be seen in Down syndrome. In anthropology, human populations have been characterized as either dolichocephalic (long-headed), mesaticephalic (moderate-headed), or brachycephalic (short-headed). The usefulness of the cephalic index was questioned by Giuseppe Sergi, who argued that cranial morphology provided a better mean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolichocephaly
Dolichocephaly (derived from the Ancient Greek δολιχός 'long' and κεφαλή 'head') is a condition where the head is longer than would be expected, relative to its width. In humans, scaphocephaly is a form of dolichocephaly. Dolichocephalic dogs (such as German Shepherds) have elongated noses. This makes them vulnerable to fungal diseases of the nose such as aspergillosis. In humans the anterior–posterior diameter (length) of dolichocephaly head is more than the transverse diameter (width). It can be present in cases of Sensenbrenner syndrome, Crouzon syndrome, Sotos syndrome, CMFTD as well as Marfan syndrome. See also * Brachycephaly * Cephalic index * Plagiocephaly Plagiocephaly, also known as flat head syndrome, is a condition characterized by an asymmetrical distortion (flattening of one side) of the skull. A mild and widespread form is characterized by a flat spot on the back or one side of the head cause ... References External links Congenital di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artificial Selection
Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together. Domesticated animals are known as breeds, normally bred by a professional breeder, while domesticated plants are known as varieties, cultigens, cultivars, or breeds. Two purebred animals of different breeds produce a crossbreed, and crossbred plants are called hybrids. Flowers, vegetables and fruit-trees may be bred by amateurs and commercial or non-commercial professionals: major crops are usually the provenance of the professionals. In animal breeding, techniques such as inbreeding, linebreeding, and outcrossing are utilized. In plant breeding, similar methods are used. Charles Darwin discussed how selective breeding had been successful in producing change over time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Anatomy
Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times. Anatomy is inherently tied to developmental biology, embryology, comparative anatomy, evolutionary biology, and phylogeny, as these are the processes by which anatomy is generated, both over immediate and long-term timescales. Anatomy and physiology, which study the structure and function of organisms and their parts respectively, make a natural pair of related disciplines, and are often studied together. Human anatomy is one of the essential basic sciences that are applied in medicine. The discipline of anatomy is divided into macroscopic and microscopic. Macroscopic anatomy, or gross anatomy, is the examination of an animal's body parts using unaided eyesight. Gross anatomy also includes the branch of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
