Mammals are animals with hair and mammary glands that give milk to nourish their young. They are vertebrates with backbones and maintain a constant body temperature. Mammals range greatly in size from tiny bats to enormous whales. Most mammals give birth to live young. There are 5,500 mammal species living in diverse environments like oceans, forests, and grasslands.
Some examples of mammal species are rats, cats, deer, monkeys, humans, bats, and whales. The defining feature of mammals is the presence of mammary glands in females to produce milk for nourishing offspring after birth. This milk production requires females to consume more food than males. All mammals possess hair at some stage of life. Most mammals also have four limbs adapted for running, swimming, flying or climbing.
The mammal class Mammalia contains around 29 diverse orders. Some of these are rodents, carnivores, primates, cetaceans and marsupials. Marsupials like kangaroos give birth to tiny young that develop further in external pouches. Monotremes such as platypuses lay eggs instead of bearing live young but have mammary glands making them mammals. Mammals first appeared during the time of dinosaurs but survived extinction by adapting to various habitats. Today they inhabit all continents and have become the most widespread vertebrate group after fish.
What classifies as a mammal?
Mammals are species of animals that have mammary glands, are warm-blooded, and have hair on their skin. Mammals give birth to live young unlike birds or reptiles that lay eggs. The three unique characteristics of mammals are: hair on their bodies, three middle ear bones, and mammary glands.
Mammals share traits that distinguish them from other animals. Some visible traits are: mammary glands to produce milk, hair or fur covering their bodies, warm-bloodedness so their body temperature is constant, direct birth of live young, efficient respiration with a diaphragm for effective gas exchange, and a muscular middle ear with three bones.
Mammals are divided into three groups: egg-laying monotremes like the platypus, marsupials that raise offspring in pouches, and placentals. There are over 5,400 mammal species including rats, cats, dogs, deer, monkeys, apes, bats, whales, dolphins and humans.
The bowhead whale can live over 200 years. The blue whale is the largest animal ever at 100 feet long and 200 tons. The smallest mammal is the 1.3 inch long, 2 gram Kitti’s hog-nosed bat. Not all mammals have hair, like whales.
Mammals belong to the chordate phylum. Their class Mammalia contains 26 orders and 5,000 diverse species in different shapes and sizes. The smallest mammals weigh around 3 grams. The largest mammal ever was the 160,000 kg blue whale.
What are mammals meaning?
Mammals are creatures that feed their young with milk. They are warm-blooded and most have hair. Some mammals are wild. Common mammals are: cats, dogs, cows, monkeys, horses, bats, elephants and whales. Some mammals like deer, cows, camels, goats and monkeys feed on grass.
Most mammals use four legs for moving around. But some mammals’ bodies are adapted for life in water, air, trees, underground, or two legs. Mammals range greatly in size from the tiny bumblebee bat to the huge blue whale. Maximum lifespan varies widely too. All modern mammals give birth to live young, except the five monotreme species which lay eggs. The placentals, the largest group, have a placenta to feed the fetus during pregnancy.
The word “mammal” comes from the Latin “mamma” meaning breast. Mammals are called mammals because they suckle their young. Most mammals give birth but some like the monotremes lay eggs yet have mammary glands.
Another mammal trait is warm blood, allowing them to regulate body temperature and live in diverse environments. There are over 5,400 mammal species found almost everywhere. Common types are rodents, primates, carnivores and ungulates.
Mammal classification is based more on reproduction than anatomy. Scientists have studied mammalian reproduction for insights into evolution.
Examples of mammals are humans, lions, dolphins, bats and elephants. Examples of non-mammals are birds, fish, insects and reptiles.
Key traits mammals share are: hair/fur, milk glands, warm blood, backbone, breathing air, live birth. Female mammals have milk glands to nourish babies. Mammals are highly intelligent.
Mammals originated from cynodonts during the Late Triassic after dinosaurs went extinct. They have dominated for the last 66 million years.
How many mammal species are there?
There are approximately 6,400 recognized species of mammals worldwide. However, the number could be higher, as new species continue to be discovered. Mammals possess characteristics like hair, mammary glands that produce milk, and typically give birth to live young.
There are more than 5,500 living mammal species, arranged in about 125 families and 27-29 orders. Contrastingly, the order Tubulidentata contains one living species. In the past, greater diversity existed in orders like elephants and horses.
About 490 mammal species are in the United States. Indonesia has the most, narrowly beating Australia regarding total fish species. The largest odd-toed ungulate is the white rhinoceros. It’s staggering to think over 6,000 mammal species are identified, and 25 new ones discovered yearly. As we explore the world, what other discoveries await?
There are 17 terrestrial mammal orders in Australia made up of 4 groups- monotremes, marsupials, rodents and bats. Some species like rats, mice and bats cannot be accurately counted. All mammals share characteristics, but differences like flight may have favored bats as viral hosts.