Placental mammals contain different types of orders. These orders include: chiroptera, pholidota, carnivore, perissodactyla and artiodactyla. Each order consists of different animals. These animals hold their young within the mother until development is well along. The eggs contain little yolk, but the extra embryonic membranes form an umbilical cord and placenta.
The name means scaly ones. The major diagnostic characteristics are the scales that cover their bodies. It had mode of keratinized epidermis. According to the behaviour and ecology of this order, some are terrestrial where as some are arboreal. Arboreal ones have prehensile tails and the terrestrial ones have short tail. These small orders consist of some very unusual animals known as Pangolins.
Pangolins are small group of mammals that feed mostly on aunts. Pangolins lack teeth. Pangolins have long tongues that are used to capture ants, termites and their main food. Pangolins have power legs which are used for digging on hard ground. The front claws of pangolin are long. It had large tail but short legs with sharp claws. New born of pangolins are razor sharp. The skull of pangolins is smoothly conical. The palate is long in pangolins. They have no jugal and the zygomatic arch is incomplete. Pangolins mandible is narrow and weak. The pyloric part of stomach is thickened and muscular.
These are only mammals that are truly fly and well furred bodies, membrane naked-transparent. Animal that fall under this order have very poor vision and use echolocation to find prey and navigate. Most of these animals are active from dusk to dawn known as nocturnal. This orders it consist of animals known as bats.
Bats are mammals found in order chiroptera. Bats have true power wings. Their forelimbs are developed as wings making them capable to flight. Their hind limbs are variously specialised but generally weak. Their incisors are generally reduced. The length of head and body ranges from 3 to 40cm. The finger bones of bats are more flexible because cartilage in their fingers lacks calcium and other minerals near the tip. The skin on their wings membranes is more elastic and can stretch more. Bats are fall under the nocturnal group, and use echolocation to navigate at night and find food. Their eyes are small and inefficient. Their ears are usually well developed. Bats have tail membrane that is used like rudder when flying.
Carnivores are strictly meat eaters. Carnivores are large in size. They all have hair. Many are nocturnal. The teeth are well developed. All carnivores have sharp canines teeth. All carnivores have strong claws and chest muscles. They have 4 to 5 digits on each leg or arm. Most of carnivores have relatively large brains. Dogs, cats, lion, walrus and sea lion are examples of carnivores. Now let’s look at animal called walrus.
The skin of walrus is pink or red in colour. The face and body are covered by short hair that are reddish brown or pink on bulls and brown on cows. Walrus are heavily built with fat body. The features of the head are squarish snout. The eyes are small and ears are internal.
Perissodactyla are small orders of herbivores consisting of herbivores, horses and tapirs. This order contains animals that are not considered as relatives to the horse. The name Perissodactyla means odd-toed. All perissodactyla are large animals. Their cheek teeth are massive, strong and modified for grinding.
Animal fall under this order have complete set of incisors. And elongate skull. These animals do not have true horns
The order artiodactyla includes deep, pigs, cattle, goats, giraffe, camels and sheep. The toes are covered by large honey hooves. Artiodactalya all have long limbs. Many Artiodactalya have horns or antler that grows from frontal bones of their skull. All Artiodactalya are carnivores. Let’s look at giraffe as an example; it is the tallest animal in the world. The front leg of the giraffe is longer than the back legs. They also posses long neck. The whole body of giraffe is covered with a spots.
Cetaceans include the blue whale, the dolphins and the porpoises. They are mammals which are warm blooded animals, they have few hairs on their bodies, and they spend their whole life in water. All porpoises and dolphins as well as minke whale are baleen whales. The body of dolphins consists of the following parts, dorsal fin tail fluke, pectoral flipper, eye and blowhole. The organism which belong to the order called cetacean usually have the following characteristics, large body size, bubbler, usually hairless, sensory abilities such as large brain and they are good in swimming.
Wikipedia contributors. Mammal [Internet]. Wikipedia, the free enclyclopedia, 00:51, 10 May 2006UTC[Cited 12 May, 2006, 5:25] Available from http://en.wikipedia.org/wiki/Mammals
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