A bat is a nocturnal, wing-handed, flying mammals, having the forelimb peculiarly modified so as to serve for flight, and constituting the order Cheiroptera (Chiroptera). Bats are sub-divided into two groups; Megachiroptera (the megabats) and Microchiroptera (the microbats).
Bats are structurally not very different from typical mammals except for the extension of their finger bones to carry flight membranes, and their backward bending knees, though their conquest of the air is a marked difference. Echolocation in bats is associated with large ears and in some cases facial skin growths, and the ability to catch flying insects at night. This food source is seasonal, which, combined with their small size, has favoured the evolution of hibernation. Daily torpor, in which the body temperature drops to the ambient temperature is common among temperate bats, and is another energy-saving adaptation necessitated by small bodies engaged in such a high energy activity as flying. Short migrations to roosts of appropriate temperatures occur throughout the year. Mating begins in the autumn, and continues at intervals throughout hibernation. Sperm is stored and ovulation and fertilisation take place in the spring with a typical litter of just one young occurring. The parent shows a strong degree of attachment for her offspring, and when they are captured, will follow them, and even submit to captivity herself rather than forsake her charge.
Bats are common in temperate and warm regions. but are most numerous and largest in the tropics. All European bats are small, and have a mouse-like skin. The body of the largest British species, Vespertilio noctula, is less than that of a mouse, but its wings stretch about 38 cm. During the day it remains in caverns, in the crevices of ruins, hollow trees, and such-like lurking-places, and flits out at evening in search of food, which consists of insects.
Several species of the same genus are common in North America, Many bats are remarkable for having a singular nasal cutaneous appendage, bearing in some cases, a fancied resemblance to a horse-shoe. Two of these horse-shoebats occur in Britain. Bats may be conveniently divided into two sections - the insectivorous or carnivorous, comprising all European and most African and American species; and the fruit-eating, belonging to tropical Asia and Australia, with several African forms. An Australian fruit-eating bat (Pteropus edulis) commonly known as the kalong or flying-fox, is the largest of all the bats; it does much mischief in orchards. At least two species of South American bats are known to suck the blood of other mammals, and thence are called 'vampire-bats' (though this name has also been given to a species not guilty of this habit). The best known is the Desmodus Rufus of Brazil, Chilli, etc. Research Bat
The beaver (Castor) is the only genus of the family Castoridae. The family contains a single genus, Castor, with two species: Castor canadensis, found in the New World, and Castor fibre, found in the Old World. Both species are semi-aquatic rodents noted for the building of dams. The two species differ chiefly in the shape of the nasal bones and are so much alike that some authorities consider them to be varieties of the same species. They are large rodents; the average adult beaver weighs about 16 kg, but specimens as heavy as 40 kg have been found, and some extinct beavers were almost bear- like in size. The beaver is usually about 76 centimetres long and stands less than 30 centimetres high, with a broad, flat, scaly tail about 25 centimetres long.
The body is plump, the back arched, the neck thick, the hind feet webbed, and all the digits clawed. The fur is usually reddish- brown above and lighter or greyish below. The eyes are small and the nostrils closable. The skull is massive, with marked ridges for fixing the muscles that work the jaws. The two front teeth on either jaw are like those of other rodents, wearing away more rapidly behind so as to leave a sharp, enamelled chisel edge. With these the beaver can cut down large trees. It usually selects trees five to 20 centimetres in diameter, but it can fell trees with diameters as large as 76 cm.
Beavers have a pair of anal scent glands, called castors, that secrete a musk-like substance called castoreum, probably for marking territories. The animals tend to be monogamous and have a life span of 20 years or more. The female has one litter a year, usually of two to four young.
Beavers are social animals and in areas where food is abundant and the locality secluded, the number of families in a beaver community can be rather large. The so-called beaver lodge is a unique structure. Three distinct kinds exist, their differences depending on whether they are built on islands, on the banks of ponds, or on the shores of lakes. The island lodge consists of a central chamber, with its floor a little above the level of the water, and with two entrances. One of these, the 'wood entrance', is a straight incline rising from the water, opening into the floor of the hut. The other approach, the 'beaver entrance', is more abrupt in its descent to the water.
The lodge itself is an oven-shaped house of sticks, grass, and moss, woven together and plastered with mud. The room inside is carpeted with bark, grass, and wood chips, sometimes with special store rooms adjoining. The pond lodge is built either a short way back from the edge of the bank, or partly hanging over it, with the front wall built up from the bottom of the pond. The lakelodge is built on the shelving shores of lakes. Dams are used by beavers to widen the area and increase the depth of water around their homes and are constructed either of sticks and poles or more firmly and solidly of mud, brushwood, and stones. As time goes by the beaver repairs and adds to the dam. Floating material lodges there, and vegetation growing on the top adds its roots to the strength of the dam. Frequently the beaver builds a smaller dam downstream in order to back up some water against the original dam and thus decrease the pressure of water on it from the other side. The dams are about 1.5 metres high, usually more than three metres wide at the base, and narrow at the top. A beaver dam more than 300 metres long was found in Rocky Mountain National Park, Colorado.
Beaver ponds eventually fill with sediment, and the animals move to a new location. The abandoned area becomes good meadowland. Beaver dams also help control runoff. Although the beaver is a powerful swimmer, it has difficulty dragging over the ground the logs and branches it needs for building and for food. Colonies of beavers therefore often dig canals from the pond to a grove of trees. Such canals are up to one metre wide and deep and often a few hundred metres long. The timber is then readily floated down the canal toward the pond.
Beavers have long been exploited for their fur, and for many years during the 18th and 19th centuries hundreds of thousands of beaver skins were exported to Europe from North America annually. The animals were also sometimes destroyed because of the damage they did to forests and the flooding occasionally caused by dams. Ceaseless slaughter led to near extinction of beavers in both Europe and North America. The beaver is almost extinct in Europe, but is becoming re-established in Canada and in protected areas of the USA. Research Beaver
Brachylophosaurus was a dinosaur of the Cretaceous period. Remains of
Brachylophosaurus were first discovered in 1936 in Alberta, Canada.
Brachylophosaurus was about 7 metres long, with a long tail and relatively large head, and had a simple crest formed from nasal bones which extended between the eyes to form a broad plate. Research Brachylophosaurus
Charadrius is a genus of birds which includes the lapwing, pratincole and oyster-catcher.
The genus is characterised by a long, slender, straight, or slightly recurvate bill, which is higher than broad at the base, and extremely compressed toward the end; an upper mandible with the dorsal line straight and slightly sloping at the base, somewhat convex beyond the nostrils, then straight and sloping to the point, the ridge broad and flattened as far as the prominence, afterwards extremely narrow, the sides sloping at the base, perpendicular towards the end, the edges rather sharp, the tip abrupt and wedge-shaped; the nasal groove is long and bare; a lower mandible with the angle of moderate length, the dorsal line ascending and slightly convex, the sides erect, the edges thin, the tip abrupt and wedged.
The nostrils are sub-basal, linear and near the margin. The head is of a moderate size, ovate with a rounded forehead; the neck is of moderate length; the body compact. The feet are of moderate length, rather stout; the tibia are bare for about a quarter of their length; the tarsus is slightly compressed and covered all round with hexagonal scales; the toes are of moderate length, stout, marginate, flat beneath, webbed at the base, the outer considerably longer than the inner, the first wanting. The claws rather small, arched, moderately compressed and obtuse. The plumage is generally blended and compact on the back. The wings are long and pointed, the first quill being the longest. The tail is short, nearly even, and comprised of twelve feathers. The tongue is short, triangular and fleshy; The Oesophagus is dilated into a fairly large crop; the stomach rectangular, muscular, with the epithelium dense and longitudinally rugous; the intestine is long and rather slender; the coeca is long and nearly cylindrical; the cloaca globular. Research Charadrius
The elephant is the two surviving species of the order proboscidea, the African elephant (Loxodonta) and the Asian elephant (Elephas) which are both very similar, except that the African elephant is generally slightly larger and has very large ears. The African elephant also differs from the Asian elephant in having a roughened trunk with two processes instead of one at the end, three rather than four nails on the hind foot, coarser molars with thicker enamel, a more convex forehead and relatively larger eyes.
Behaviourally the two species are very similar, except that the African elephant generally sleeps standing up. Perhaps the most striking feature of the elephants is the long prehensile trunk formed from the nose and upper lip. The trunk contains nasal passages and nostrils at the tip. Elephants are gregarious animals, travelling in herds of up to 100 animals, and inhabiting forests and grassy plains where they eat only plant matter, the African elephant rarely eating grass but preferring leaves, fruit and the inner bark of some trees. Elephants start breeding when about 15 or twenty years old, but are not fully grown until they are 25 and live to about 50 years of age. The gestation period is 20 months, and a single young or very rarely twins, is born with a cow giving birth to four or five young during her life. Research Elephant
Alar nasal cartilage makes up the apex of the nose. The apex of the nose is made up of paired lateral alar cartilages. Each lateral alar cartilage has a shape similar to a horseshoe and partially encircles the nostril. These make up the large, flat lateral wall and the inferior extension makes up the medial wall. The medial wall forms the movable nasalseptum, which divides the nasal cavity. Two to four lesser alar cartilages (sesamoid cartilages) are also found on each side of the nose at the back end of the lateral wall of the alar cartilage. Research Alar Nasal Cartilage
Anosmia is the inability to smell, or the loss of the sense of smell. It is usually the result of a lesion of the olfactory nerve, disease in another organ or part, or an obstruction of the nasal passages. Research Anosmia
The canthus is the notch at each edge of the eye, where the two eyelids meet. The inner, or medial, canthus is called the nasal canthus, because of its proximity to the nasal structures. The outer, or lateral, canthus is called the temporal canthus because of its proximity to the temporal region of the skull. The nasal canthus features the fleshy, pink lachrymal caruncle and the canaliculi which lead into the lachrymal sac. Research Canthus
The choanae are the posterior nasal apertures, visible in the inferior vier of the skull. The two choanae are separated by the posterior border of the vomer, and are evident at the rear of the palatine bones. Research Choanae
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Bat
