Though most mammals all share certain features or characteristics, some of them do stand out from the crowd. Their lungs play an important role in the exchange of oxygen and carbon dioxide.
All mammals breathe air, even the ones which live in the ocean. Their circulatory system (how blood is sent around the body) is highly efficient and a four-chambered heart is one of the exceptional features of mammals. They also have three bones in their middle ear. Hair is another important feature in mammals and it is present on their body at least at some point in their life. They have special glands called mammary glands which produce milk for feeding their young after they are born. Mammals are endotherms, which means that their bodies can generate heat in order to maintain a suitable body temperature. Mammals are grouped by some basic characteristics that all of them share. A manatee’s teeth are replaced continuously. Polar bears have thick fur to keep warm. 
A chimpanzee, one of the most intelligent mammals. The bumblebee bat, smallest mammal in the world. Have a look through the gallery and see if you can spot these images: His long, shaggy hairs are colourless and hollow. A polar bear looks white, but he isn't really. Missing a meal is a sure way to a quick death. Shrews have so little body fat they cannot go more than a couple of hours without food. Some mammals, such as the anteater and the Baleen whales, do not have any teeth. The Virginian opossum has one of the shortest gestation periods of just 12 days. The mammal with the longest gestation period (being pregnant with a baby) of 22 months is the elephant. Lots of people think that birds are mammals but, although they are warm-blooded, they belong to a group called ‘aves’. Bats are the only mammals that are capable of flying. Its call can be as loud as 188 decibels, which is as loud as a bomb going off! The loudest mammal on Earth is the Blue Whale. There are more rats and mice than any other kind of mammal on the planet…. Once the dinosaurs became extinct, the mammals began to thrive. The most abundant mammals were small, nocturnal and fed mostly on insects to survive. Mammals evolved alongside the dinosaurs. Mammals have several different kinds of teeth, which allows for more efficient processing of food. Mammals that eat both meat and plants are called omnivores. Mammals that eat only plants are called herbivores. Mammals that eat meat are called carnivores. The largest mammal is the blue whale (weighing 160,000kg) and the smallest is the bumblebee bat (weighing 2g). There are between 4,500 and 5,500 species of mammals. Whales and dolphins would have had limbs but over time, have lost them in the process of evolution. Nearly all mammals are able to move around using limbs and are known as tetrapods (which means four limbs). Some mammals, such as chimpanzees, dolphins, and especially human beings, are highly intelligent. Mammals have a larger, more developed brain than other animals. Their body temperature remains about the same all the time, even though the temperature of their surroundings may change. All mammals have hair or fur at some time in their life, though in certain mammals, such as whales, it is present only before birth. Most mammals give their young more protection and training than other animals do. 
All mammals (apart from the duck-billed platypus) give birth to live babies, which are then fed on their mother’s milk. Some mammals, such as dolphins, seals and whales, live in the sea. Arctic foxes and polar bears make their home near the North Pole. Mammals such as chimpanzees and elephants live in tropical regions. Mammals are found all over the world in all sorts of different environments and climates. Mammals also include other unusual and fascinating animals such as porcupines, gorillas, giraffes, rhinoceroses and kangaroos. So are farm animals such as cows, goats, pigs, and horses. If you can think of an animal, there is a very good chance that it will be a mammal.
0 kommentar(er)
