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Here is an essay on the ‘Vertebrates’ for class 9, 10, 11 and 12. Find paragraphs, long and short essays on the ‘Vertebrates’ especially written for school and college students.
The animal kingdom includes more than ten lakh animal species. They are different in shape, size behaviour, life-cycle etc. Some are unicellular and microscopic; while others are multicellular and huge. Some are devoid of skeleton (bones), while others possess skeleton. In such cases, it is very difficult to study them. To remove such difficulties, the scientists have laboured hard and classified them on the basis of similarities and dissimilarities.
First of all, they divided them into two major Groups viz. sub-kingdoms such as Invertebrata and Vertebrata. Afterwards, Groups divided into different Phyla (Singular, Phylum) and subsequently, further, divided into Order, Family and lastly into Genus and Species. These all classifications have been done according to the evolutionary trends for better apprehension. Each species has been named by a definite scientific-name (zoological name) to be recognized worldwide.
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From wildlife management point of view, the vertebrate group is important which has been divided into mainly five Classes such as Pisces (fishes), Amphibia, Reptilia, Aves (birds) and Mammalia. Out of these, mammals are the most important in the context of wildlife.
1. Essay on Pisces:
Fishes are cold-blooded craniate, primarily adopted for aquatic life; with paired fins supported by dermal fin rays, and with gills born on true gill-arches.
Characters:
(i) They are clod-blooded (poikilothermic) craniates which are more completely adapted to aquatic life than any other craniate.
(ii) The body is streamlined to facilitate the passage through water.
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(iii) The skin is covered with scales, dermal denticles or bony plates.
(iv) The tail is muscular and is used for propulsion.
(v) The paired limbs are absent. Instead, paired pectoral and pelvic fins are usually present together with median and anal fins. They are supported by bony dermal fin-rays. They regulate the swimming.
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(vi) The endoskeleton may be cartilaginous or bony.
(vii) The alimentary canal is specialized with very short pharynx and definite stomach. In bony fishes, there are many caecal appendages connected with the alimentary canal. In many the gut ends in cloaca, where-as in others distinct anus lies in front of the genital and urinary apertures.
(viii) Paired nostrils are present which do not open into the pharynx except lung-fishes and-lobbed-finned fishes.
(ix) There are no external and middle ears. Only internal ear is present having three semi-circular canals.
(x) The lateral line system is prominently developed.
(xi) The organs are lodged in closed canals, sunk beneath the surface.
(xii) The heart is venous with one auricle and one ventricle. It pumps the venous blood to the gills for aeration. Renal and hepatic systems are present.
(xiii) The respiratory organs are gills, born on gill-arches. They open outside by gill-slits which may be covered by an operculum (Teleostomi). The gill-slits are never more than seven pairs. Usually only five pairs are found.
(xiv) Accessory respiratory organs may be present.
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(xv) There are ten pairs of cranial nerves and the kidneys are mesonephrous.
(xvi) Sexes are separate and the development is direct. Gonads possess true ducts.
(xvii) Amnion and allantois are absent in the embryonic stage.
Broadly, the fishes are classified into Cartilagenous fishes (Chondrichthyes/Elasmobranchi) and Bony fishes (Osteichthyes/Teleostomi).
There are a large number of fish species (about 20,000) and here some important orders are mentioned:-
1. Pleurotremata (Sharks):
It includes ail sharks and dog-fishes. They are marine and carnivorous.
Ex: Scoliodon etc.
2. Siluriformes (Cat Fishes):
They are without exoskeleton of scales. They live in the mud of ponds, water-reservoirs, pools etc.
Ex: Clarias, Heteropneustes, Wallago, Freshwater Shark etc.
3. Cypriniformes (Carps):
It is the largest Order of fish. Its origin is supposed in our country. The specialty of these fishes is that the teeth are found in their neck instead of mouth.
Ex: Labeo, Catla, Barbus, Cirrhina etc.
2. Essay on Amphibia:
They are amphibious tetrapods with moist, soft skin and without external scales.
Characters:
(i) They are aquatic or semi-aquatic i.e. amphibious in habit. Even when they live far away from water, they come to the water to deposit their eggs. They were the first vertebrate who could lead a terrestrial existence.
(ii) They are confined to the torrid and temperate zones. In the temperate-zones, they hibernate during winters.
(iii) The skin is soft, moist and glandular which possesses no exoskeleton; if scales are found they are hidden in the skin.
(iv) Paired-fins are absent; if present, they are not supported by skeletal- support.
(v) The limbs are present which are pentadactyle or five-toed.
(vi) The skeleton is mostly bony.
(vii) Skull possesses two occipital condyles, with which the skull articulates with the first vertebra. The pectoral and pelvic girdles are very strong.
(viii) The heart is three-chambered; the auricle is completely divided into right and left auricles.
(ix) The aortic arches are symmetrical on the two sides. There are ten pairs of cranial nerves.
(x) Lateral-line organs are wanting in the adult.
(xi) The collumella auris is present.
(xii) The functional kidney of the adult is mesonephrous.
(xiii) There are no copulatory organs in the male.
(xiv) Most of the species undergo metamorphosis, the young-ones living in. water respire by gills. They later disappear in the adult except in some lower amphibians where they are retained throughout the life.
(xv) There is no amnion and allantois.
Amphibians lay the eggs once in a year. The female visits to the water for laying the eggs which are thousands in number. From the eggs, tadpole larvae hatch out which respire through the gills like fish. In young stage, they are vegetarian but the adults are insectivorous. Amphibia includes Frogs as the chief species.
3. Essay on Reptilia:
Reptiles are amniotes with dry and scally skin.
Characters:
i. Cold-blooded, terrestrial craniates with two pairs of pentadactyle limbs.
ii. Skin is dry, rough, and non-glandular, usually with epidermal scales or scutes.
iii. Skull possesses one or more temporal vacuities and single occipital condyle.
iv. Parasphenoid is reduced or absent. Sternum is highly developed.
v. Heart is imperfectly four-chambered with two auricles and a partially divided ventricle. The latter is completely divided in crocodiles.
vi. The aortic arches are symmetrical.
vii. R.B.C. is nucleated, biconvex and oval.
viii. Renal portal system is reduced.
ix. Respiration always by lungs.
x. Central nervous system is advanced with an increased cerebrum.
xi. Twelve pairs of cranial nerves.
xii. The lateral line system is entirely absent; but the eyes, nose and ears are better developed.
xiii. Kidneys are metanephric.
xiv. Fertilization is internal.
xv. Eggs are large with much yolk; they are always laid on land and never in water.
xvi. Segmentation is meroblastic, foetal membranes (amnion and allantois) are present in development. There is no metamorphosis.
Its important orders are as follows:
1. Chelonia (Testudinata):
It includes all types of aquatic and terrestrial Tortoises.
2. Squamata:
It includes all types of Lizards.
3. Ophidia (Serpentes):
It is largest Order of reptiles. It includes all types of snakes. Snakes feed on insects, frogs, birds, fishes, eggs and even other snakes.
4. Crocodilia:
It includes crocodiles (Gharial & Mugger).
4. Essay on Aves:
They are amniotes with feathers; scales persist on legs and feet bearing claws; the anterior appendages modify for fight in most birds (carinates) but in ratites, vestigial or absent. Aves are called as “glorified reptiles”.
Characters:
(i) Aves are warm-blooded (stenothermic) bipeds.
(ii) The epidermal exoskeleton is represented by feathers and a few scales on the legs similar to those of the reptiles.
(iii) The fore-limbs are modified as wings. The hind-limbs are attached forwards to balance the weight of the body.
(iv) The endoskeleton is mostly spongy containing air-cavaties so that the body becomes light. The bones of the skull undergo early ankylosis. Only the lower jaw, quadrate, columella and hyoid are movable. There is only one occipital condyle. The premaxiilae is large and form most of the beak. In modern birds, there are no teeth.
(v) Most of the vertebrae have heterocercal centra. The cervical vertebrae have small ribs fused with the transverse processes. The thoracic vertebrae are joined together. A fused synsacrum is formed by the union of lumbar, sacral and a few caudal vertebrae. The terminal vertebrae usually use to form plough-shaped pygostyle.
(vi) There is well-developed sternum with the keel. In flying birds, the clavicles are usually well-developed and are connected by an interclavicle to form furcula.
(vii) Ribs are provided with uncinate processes.
(viii) The fore-limb has only three digits.
(ix) The three metacarpals are fused and there are only two separate carpals, others fuse with the metacarpals to form the carpo-metacarpus. The thumb is often clawed.
(x) The pelvic girdle is fused with the sacrum throughout its length. The ilium is long and extends far in front and behind the acetabulum. The pubis and ischium are directed backwards and there are neither the pubic nor ischiatic symphyses.
(xi) In the hind-limb, the fibula is incomplete and almost united to the tibia.
(xii) The proximal tarsals are fused with the tibia to form a tibio-tarsus. The distal tarsals are fused with second, third, and fourth metatarsals to form a tarsometatarsus. The first metatarsal is free.
(xiii) In the digestive system, the gullet is dilated into a crop and the stomach is divided into a glandular proventriculus and muscular gizzard. Rectal caeca are present at the junction of the intestine and rectum. A cloaca is also present.
(xiv) The non-expansible lungs are provided with air-sacs which may extend into the bones. The trachea has bony-rings. A special vocal organ in the form of syrinx is present.
(xv) The heart is four-chambered; the right auriculo-ventricular valve is muscular. There is only right aortic-arch. The renal portal system is not well-developed. The Red Blood Corpuscles (R.B.C.) are oval and nucleated.
(xvi) The brain has large cerebellum and cerebral hemispheres and the optic-lobes are laterally displaced. The eyes are usually large and have sclerotic plates and pecten. The olfactory organs are poorly-developed. The auditory organ has large curved cochlea.
(xvii) The kidneys are three-lobed. The ureters open into the cloaca. There is no urinary bladder. The right ovary usually atriphies while the right oviduct is rudimentary.
(xviii) Birds are all oviparous and lay large eggs containing large amount of yolk and albumen.
(xix) They have double shell-membrane and calcareous-shell. During development, the embryo develops embryonic-membranes such as amnion, allantois and yolk-sac.
There are about 8700 species of birds in the world.
Some important orders are as follows:
1. Struthioniformes (Ostriches):
This Order includes true Ostriches found in the plains and deserts of Africa. They lay very large eggs.
Ex: Ostriches.
2. Pelecaniformes (Pelicans, Cormorants, Darters):
These are large aquatic birds.
Ex.: Pelicans, Cormorants, Darters.
3. Ciconiiformes (Storks, Herons):
They mostly live in marshy places having great power of flight.
Ex.: Storks, Herons.
4. Phoenicopteriformes (Flamingoes):
It includes large sized and long-legged marshy birds feeding on fishes.
Ex.: Flamingoes.
5. Anseriformes (Ducks and Swans):
They are aquatic and have broad and depressed beak.
Ex: Ducks and Swans.
6. Falconiformes (Falcons and Hawks):
They have sharp-edged, strong and curved beaks, hooked at the extremity. Toes adapted for perching and bear powerful claws suited for seizing and tearing the prey. They mostly feed on small birds or mammals, but vultures feed on dead animals (carrion).
Ex.: Falcons, Vultures, Kites, Hawks, Eagles, Buzzards.
7. Galliformes (Game Birds):
The Order includes mostly terrestrial birds which scratch ground in search of grains, insects etc.
Ex.: Peacock, Jungle-fowl of India (Callus gallus) etc.
8. Gruiformes (Rails, Coots, Bustards, Cranes):
Most of them are shore-birds frequently the edges of rivers and lakes having weal power of flight. They feed on fishes, reptiles, molluscs etc.
Ex.: Rails (Gaillinula, Amaurornis), Coots (Fulica atra), Bustards (Ostis, Neotis), Cranes (Sarus crane, Antegone antegone).
9. Cucuiliformes (Cuckoos):
They have long pointed wings. Beak is gently curved and deeply cleft feeding on fruits. They usually build nests.
Ex.: Koel (Eudynamis) which lays its eggs in the crow’s nest where they lire incubated.
10. Coraciiformes (Bee-Eaters, King-Fishers):
They are mostly tropical with bright plumage. Their anterior toes are united.
Ex.: Bee-eaters, King-fishers.
11. Piciformes( Woodpeckers):
This Order includes strongly build and wood-boring wood-peckers which hunt on insects from under the bark of the tree. The beak is hard, chisel-shaped and powerful.
Ex.: Woodpeckers.
12. Psittaciformes (Parrots):
They are arboreal in habit; it is cosmopolitan but is mainly found in warm climate. It mainly feeds on fruits. No nests are made.
Ex.: Parrots, Cockatoas etc.
13. Strigiformes (Owl):
It includes owls which are nocturnal hunting small mammals like squirrels, rats and mice. Ex.: Owls.
14. Caprimulgiformes (Goat-Suckers):
They are nocturnal and owl-like in appearance. They inhabit forests and prey on insects during flight.
Ex.: Caprimulgus (found on the plains throughout India and Ceylon).
15. Micropodiformes (Humming Birds):
This Order includes humming birds which are very small birds feeding on insects.
Ex.: Micropodus (Indian swift), Cypsilurus (Palm swift) humming birds found in India.
16. Pterocletiformes (Grouses):
These are commonly known as sand-grouses and have immense power of flight. They are usually found in dry sparsely wooded sandy semi-desert plains.
Ex.: Grouses.
17. Columbiformes (Pigeons):
The Order includes pigeons which are grain or fruit eating birds with weak and slender beak.
Ex.: Pigeons.
18. Turniciformes (Quails):
It includes small birds like bustard quails.
Hind toe is absent. They teed on seeds, tender-shoots and insects. After laying the eggs, the female goes in search of a fresh mate so to make the maximum use of the breeding-season and the eggs are left to be incubated by the male.
Ex.: Turnix.
19. Passeriformes (Crow):
This Order includes more than half of the total number of living species. The feet are adapted for perching as three of the toes are directed forwards and one backwards. Many species built elaborate nests.
Ex.: Crow etc.
5. Essay on Mammalia:
They are amniotes with hair and mammary glands.
Characters:
(i) Mammals are warm-blooded animals with a hairy covering. The hair are of epidermal structures which serve to prevent the loss of heat from the body. The hair may form a thick covering for the body or may be sparse. Hairs are never entirely absent. They are scanty in Sirenians and Hippopotamus and absent in Cetacea in which they are restricted to embryonic-stage.
(ii) The skin has sweat glands and sebaceous glands. In the female, milk-giving mammary glands develop as specialization of skin glands.
(iii) The skeleton of mammals shows a few characteristic points. The bones of the skull are firmly united by sutures which generally persist. Only the lower jaw, the ear ossicles and the hyoid are movable. There are two occipital condyles as in Amphibia. The prefrontals, postfrontals, quadratojugals, supraorbitals and basipterygoid are absent. The lower jaw on each side consists of a single bone which works on the squamosal.
(iv) The hyoid consists of a median basihyal and two pairs of bones connected with it. The anterior horn is composed of three segments; the ceratohyal, epihyal and stylohyal. The posterior horn consists of a thyrohyal which connects the basihyal with the thyroid cartilage.
(v) The vertebrae have terminal ossification or epiphysis. The centra of the vertebrae have flat or slightly rounded faces. There are usually seven cervical vertebrae.
(vi) The coracoid is usually represented by a small process from the scapula and sometimes by a small ossification in the glenoid cavity.
(vii) The sternum includes a presternum with which the clavicles articulate, a mesosternum divided into segments with which the sternal parts of the ribs articulate and xiphisternum which is cartilaginous. The acetabulum is usually completely ossified.
(viii) The digits in the fore and hind limbs are never more than five but are often reduced. When the digits are reduced, there is usually an elongation and fusion of the metacarpals and metatarsals to form the common bones.
While walking, the whole of the lower surface of the hand and the foot may rest on the ground (plantigrade) or only the two distal joints may rest on the ground (digitigrade) or only the last joint in each limb (unguligrade). There are also intermediate conditions like semi-plantigrade and semi-digitigrade.
(ix) There is generally a distinct neck between the head and the trunk. The vertebral column is in most cases prolonged into a tail.
(x) A complete muscular partition or diaphragm separates the chest- cavity containing heart and lungs from the abdominal-cavity. The diaphragm is of great importance in respiration.
(xi) The alimentary canal ends separately from the urinogenital aperture. The dentition is heterodont, having four different types of teeth.
(xii) The brain shows a bigger grade of evolution. The cerebral hemispheres have usually the convoluted surface and always cover the optic-thalami and optic-lobes and in higher form the cerebellum as well. The commissural system is well developed being specially represented by a large corpus callosum except in monotremes and marsupials in which the anterior commissure is large and the corpus is absent or very small.
There is also an important set of longitudinal fibres called the forenix. Another characteristic of mammals is the differentiation of an area of cerebral cortex which has been called the neopallium which is the reception area of optic, auditory and other stimuli, the area of associate memory and of attentive manipulations.
(xiii) The heart is four-chambered and there is only one aortic trunk on the left side. The Red Blood Corpuscles (R.B.C.) are non-nucleated and appears as slightly biconcave discs, circular in outline. There is no renal portal system.
(xiv) The lungs are invested by pleural sacs, lying in the chest cavity. Within the lungs, the branchial tube fork repeatedly into finer and finer branches. At the top of the trachea, there is a complex larynx with the vocal-cords.
(xv) The kidneys are generally compact and rounded bodies. The ureter, except in monotremes, opens into the bladder. The outlet or urethra of the bladder unites in the male with the genital duct to form a urinogenital canal. In the female, except in monotremes and a few others, the urethra and the genital duct open into common vestibule.
(xvi) In the primitive mammals, the testes are abdominal but in the majority they descend permanently into a single or paired scrotal sacs lying behind the penis.
(xvii) The ovaries are small. Except in monotremes, the genital ducts of the female are differentiated into fallopian tubes which catch the ova, the uterus where youngs develop, and vagina which ends in the urinogenital aperture.
In monotremata, the two ducts are simple and open separately into the cloaca. In metatheria, there are two uteri and two vaginae. In eutheria, the uterine regions are more or less united and the vaginal regions are always completely fused.
(xviii) In prototheria, the eggs are large and rich in yolk. In others, they are small and without any yolk. In monotremes, the cleavage is meroblastic while in others it is holoblastic.
(xix) There are two foetal membrances – the amnion and allantois – both of which share in forming the placenta of eutherians.
(xx) Monotremes are oviparous, the marsupials bring forth their youngs prematurely after a short gestation while in eutherians a true allantoic placenta may be present which provides nourishment to the developing embryo.
(xxi) Practically in all the mammals, the youngs for a longer or shorter period are dependent upon the milk secreted by the mammary-glands of the mother.
Class Mammalia has been divided into three sub-classes like Prototheria, Metatheria and Eutheria:
1. S.CI. Prototheria (Monotremata):
They are very small group of primitive egg-laying mammals restricted to Australia and the neighbouring island of Tasmania and New China.
Ex: Ornithorhynchus, Echidna.
2. S.CI. Metatheria (Marsupiaiia):
With the exception of the American Opossum, all the marsupials are the native of Australia. They have marsupium or brood-pouch in which immature young- born is kept and fed with milk by the mother.
Ex.: Opossum, Banded Ant-eater, Kangaroo etc.
3. S.CI. Eutheria:
They are provided with true allantoic placenta and the embryos are retained in the uterus till an advanced stage.
From wildlife pint of view, the important orders of Eutherians are as follows:
(i) Insectivora:
They are the most primitive small eutherians.
Ex: Hedgehog, Moles, Shrews.
(ii) Chiroptera:
These are the only mammals possessing the power of flight. The fore-limbs are modified as wings.
They have been divided into two sub-orders:
(a) Microchiroptera:
It includes insectivorous and carnivorous bats. Though they are comparatively smaller in size but some are bigger in size even than megachiroptera.
Ex. Horse-shoe Bat (insectivorous), Vampire Bat (carnivorous).
(b) Megachiroptera:
They are vegetarian bats (fruit eaters) and generally larger in size.
Ex.: Flying-fox Bat, Short-nosed Fruit Bat.
(iii) Edentata (Xenarthra):
They are arboreal mammals passing their whole life among the branches to which they hang. They are solitary, nocturnal, vegetarian animals being sluggish in nature and are found in South and Central America.
Ex.: Sloths etc.
(iv) Rodentia:
The rodents are represented in all parts of the world. They are typically vegetarian. The incisors are chisel-shaped. There are no canines and there is a space known as diastema-between incisors and premolars.
Ex.: Squirrel, Porcupine, Rat, Mice, Rabbit etc.
(v) Carnivora:
This Order is considered a highly specialized offshoot of insectivora. It includes more than 600 species. They are carnivorous in nature feeding on animal diet and the most typical forms of prey and devour the warm flesh of other animals. Most are fierce animals with keen senses and quick intelligence.
The teeth are always rooted and canines are strong and sharp. The incisors are small and always three on each side in each jaw. The last premolar in the upper jaw and the first molar in the lower jaw have blade like cups called as caranassial teeth.
The important families are:
(a) Felidae:
It includes the most specialized forms and exclusively adapted for a flesh diet. The canines are large and the molars are reduced to 1/1. The caranassial teeth are well-developed. The limbs are digitigrade and claws retractile.
Ex.: Lion, Tiger, Leopard (Panther), Snow leopard, Cats, Leopard cat, Flying cat, Jungle cat, Desert cat, Caracal, Cheetah (now extinct from India) etc.
(b) Viverridae:
The family includes old world forms like civets. They are comparatively small in size and have long head and body with pointed muzzle. Most of them have a scent gland beneath the tail.
Ex.: Civets (Small Indian Civet, Common Palm Civet or Toddy Cat, Himalayan Palm Civet) etc.
(c) Herpestidae:
They are like viverridae but the difference is that they attack on prey openly and directly while the animals of felidae and viverridae families do not attack their prey openly but by hiding.
Ex.: Mongoose.
(d) Hyaenidae:
Four digits in the fore and hind limbs. Claws short. The family is represented by Hyaena of Africa and South Asia. Only Striped-hyaena is found in India. Its front body is bigger and strong but the posterior part of the body is weak and that’s why it is unable to kill its prey and feed on the carrion of the prey killed by other carnivores.
Ex.: Hyaena, Striped-hyaena.
(e) Canidae:
Digitigrade claws are not retractile. The paroccipital processes are long. Legs are long and slender. The caecum is small.
Ex.: Wolf, Jackal, Dog, Fox etc.
(f) Ursidae:
Five digits in fore and hind limbs. The molars have broad tuberculated crowns and are used for grinding. Caecum is absent. They have omnivorous diet.
Ex.: Sloth bear, Brown bear, Black bear etc.
(g) Mustelidae:
They have in general a long neck, slender flexible body and short limbs.
Ex.: Otter, Badger, Weasel etc.
(vi) Ungulata:
This is the largest order which includes all the hoofed- mammals. They are herbivorous. It is divided into two Sub-orders such as Artiodactyla and Perissodactyla.
(A) Artiodactyla:
They have even number of digits in-both fore and hind limbs. The premolars and molars are unlike and are generally bunodont or selenodont. The stomach is complicated and caecum is small.
It has following important families:
(i) Hippopotamidae:
The skin is very thick with a few hair restricted to the snout, head, neck and tail. They spend the day in the rivers and lakes and at night come on land for grazing herbivorous. There is no caecum.
Ex.: Hippopotamus.
(ii) Suidae:
The important animal of this Family is wild boar which is found in the whole India. Nostrils are terminal and the snout is mobile. There are four digits but only the third and the fourth reach the ground while the animal walks.
Ex.: Wild boar (Bears and Pigs).
(iii) Giraffidae:
The family is represented by Giraffe. The tall animal is notable for elongated cervical vertebrae (neck) and long limbs. Herbivorous animal.
Ex.: Giraffe.
(iv) Bovidae:
This is the largest family of Artiodactyla including all wild and domestic cows, oxes, buffalos, bison, sheep, goats, antelopes and gazelles. Each hoof is divided into two parts. The fifth and second digits may be absent. They are herbivorous and, hence, their teeth are adapted for the purpose.
The upper incisor teeth are absent. The stomach is divided into four parts. The horns are not deciduous and persist throughout the life. They are usually present in the both sexes though larger in males.
The horns are made up of two parts. One part is internal (core of bone) and arises from the skull bone and the other outer part is the cover and hollow (hollow-sheath) which can be detached from the internal part. The horns may be erect, semilunar or wrinkled but do not have branches.
The family has been divided into following sub-families:
i. Bovinae:
It includes domestic as well as wild cows and allies.
Ex.: Cow, Ox, Buffalo, Indian Bison (Gaur), Wild Buffalo, Yak etc.
ii. Caprinae:
It includes wild and domestic goats and it’s allied.
Ex.: Goat, Sheep (Ibex, Markhor, Tahr, Nayan, Bharal, Shapu or Urial) etc.
iii. Antelopinae:
They resemble with bovinae and caprinae but have some specialities. It is supposed that two offshoots like bovinae and caprinae evolved from antelopinae-stalk.
Ex.: Antelopes (Tibetan Antelope or Chiru, Blackbuck or Indian Antelope), Gazelles (Chinkara or Indian Gazelle) etc.
iv. Tragelaphinae:
They differ from antelopinae bearing comparatively smaller horns without rings as well as females are devoid of horns.
Ex.: Blue Bull, Four-horned Antelope (Chowsingha).
v. Rupicaprinae:
These are the animals between caprinae and antelopinae. Ex.: Goral, Serow etc.
(e) Cervidae:
This is commonly known as deer family. The upper canines are usually present in both sexes. The horns present are called as Antlers which are deciduous and usually confined to the males which are the outgrowth of the frontal bones.
Ex: Deer (Spotted deer or Cheetal, Swamp deer, Barking deer, Hog deer, Mouse deer, Musk deer, Brown-antlered deer, Hangul etc.).
(B) Perissodactyla:
They have odd (uneven) number of digits in both fore and hind limbs. They are herbivorous. Premolars and molars teeth form a continuous series with broad transversely ridged crowns. The stomach is simple; the caecum is large and sacculated. There is no gall bladder. There are no horns.
The two important families are:
(a) Equidae:
They have only one (third) as the functional digit. Tail is long and hairs begin from close to the base of tail or half way down. The incisors are chisel-shaped.
Ex: Horse, Ass, Wild Ass, Zebra.
(b) Rhinocerotidae:
They are large heavy ungulates, shy and nocturnal fond of living in water and mud. They are herbivorous. The skin is very thick with scanty hair. One or two median horns grow as huge waste from the snout and forehead. In India, only Great One-horned Rhinocerus is found as the representative of this family.
Ex.: Rhinoceros.
(vii) Proboscidea:
The long mobile proboscis (trunk), the characteristic dentition, the large and massive body is the distinguishing features of this Order. Proboscis is a muscular expansion of the nose and bears the nostrils at its tip. The skin is strong and the hairs are scanty. The facial region is short. The skull is large being adapted to support the trunk as well as tusks and to afford a broad insertion for the large muscles.
The bone contains air-sinuses which are continuous with the nasal passages. The legs are large and pillar-like and not bent at the knee. The pinnae are very large (fan-like) and eyes are small. They are herbivorous. All the canine teeth have been lost, and all the incisors except the second pair in the upper jaw which have developed in tusks (solid ivory). The premolars are small and shed yearly. The molars are very large.
The Order has only one Family Elephantidae including living Asiatic and African elephants.
Ex.: Elephants.
(viii) Sirenia:
They are sluggish animals with massive heavy bones, a plumpy body with sparse hair on the thick and tough skin. They are adapted to aquatic life having fish-like form.
Ex.: Dugong, Manatee.
(ix) Cetacea:
It comprises whales and dolphins adapted to aquatic life having fish-like body. A thick layer of fat is present beneath the skin (adipose tissue) which prevents the loss of heat and diminishes the specific-gravity. The hair is restricted near the mouth as a few bristles.
Ex.: Whale, Dolphin.
(x) Primates:
This Order is the most advanced in the trees of organic- evolution and includes monkey, apes and man showing the advanced intelligence. The thumb is opposable. From Indian wildlife point of view, the two Families are important.
(a) Cercopithecidae:
The sternum is long and narrow. The snout or muzzle is often dog like. The foramen-magnum is directed backwards. The arms are shorter than the legs. There are usually cheek-pouches. The caecum is conical and without a vermiform appendix.
Ex.: Macaque (Monkey), Langur, Proboscis Monkey, Indian Monkey, African Babboon, Mandrill (noted for the bright colours of the face and hips of the males) etc.
From Indian point of view, the Macaque and Langur are important. Macaque is comparatively stronger and has cheek-pouch in which food is stored for sometimes. Macaques are of different kinds; but those which are found in North and Central India are red-faced and called as Rhesus Macaque.
Langurs are comparatively bigger in height but thin and have no cheek-pouches. They are also found in different kinds but the most common langurs are black- faced in the whole India except western-desert.
(b) Simiidae:
The sternum is short and broad. The arms are longer than the legs. The apes tend to walk on the edges of their feet. There are no cheek-pouches. The caecum has a vermiform appendix.
Ex.: Gibbon, Gorilla, Chimpanzee (Ape).
In India, only a single species of gibbon/ape is found which is Hoolock or White-browed Gibbon in the forests of Assam. Like all apes, they are tailless but distinctive in the great development of the arms which are much longer than the legs.