Mammals

Mammals are warm-blooded vertebrates that have four limbs, hairs, and complex brains. They also have mammary glands that produce milk to feed their young. Mammals can be classified into three groups: egg-laying monotremes, marsupials, and placentals. Some examples of mammals include Humans, Dogs, Cats, Whales, Dolphins, Bats, and Elephants. In this article, we will discuss mammals and how they are classified based on their characteristics with some of the examples.

What are Mammals?

Definition of Mammals: Mammals are warm-blooded vertebrates that have backbones, hair or fur, mammary glands, and the ability to give birth to live young.

Mammals are animals that fall under the class Mammalia. They are among the most evolved species in the animal kingdom and are classified as vertebrata. They are distinct from all other animals due to their advanced features. They are characterised by hair, mammary glands for nurturing young with milk, a diaphragm, three middle ear bones, and a lower jaw consisting of a single pair of bones that articulate uniquely with the skull.

Their mammary glands, which they use to nurse their young, are what distinguish them. They can be found all over the world and have adapted well to their environment, which includes rivers, rainforests, polar regions, deserts, and oceans. Mammals can regulate their body temperatures and internal environment in extreme heat and dryness, as well as in severe cold. This versatility in surviving and thriving on Earth is largely attributed to their unique ability. The world is home to about 6,000 different species of living mammals.

Characteristics of Mammals

Characterisctics of Mammals are as follows:

• Mammals are animals with warm blood that give birth to their offspring.
• In practically every kind of habitat, they are the most prevalent animal form.
• Their mammary glands aid in the production of milk, which they use to nourish their young.
• The brain region referred to as the Neocortex is present.
• Sebaceous glands, which produce animal oil, and sudoriferous glands, which produce sweat, are found in their skin.
• Animals’ ability to adapt to their surroundings is aided by the fur and hair on their bodies.
• They are heterodont, i.e., possess different types of teeth.
• Mammals also possess cervical vertebrae.
• The skull is dicondylic.
• The trunk is divided into thorax and abdomen.
• The lungs are used by mammals to breathe.
• Good sense of hearing because mammals have three middle ear bones to help them hear.
• Mammals have a four-chambered heart. The sinus venous and renal portal system are absent.
• lower jaws with a single bone present.
• The cerebrum, cerebellum, and medulla comprise the well-developed brain.
• Exhibit one of the most advanced forms of diaphragms. They have twelve pairs of nerves in their skulls.
• The mammals can lay eggs as well. They are known as viviparous.

Types of Mammals

Mammals appeared over 200 million years ago during the dinosaur era. While initially small, their evolution surged after the extinction of dinosaurs around 66 million years ago, resulting in the development of larger forms. Distinguished by warm-bloodedness and fur, mammals thrive in a variety of habitats worldwide, spanning from icy polar regions to lush tropical forests. Generally, mammals fall under the kingdom Animalia, phylum Chordata, and class Mammalia. The widely accepted categorization of mammals is based on three major reproductive methods:

• Monotremes Mammals
• Marsupial Mammals
• Placental Mammals

Monotremes	Marsupials	Placental mammals
Give birth to live, fully developed young Examples-Opossum and koala, Dog and anteater, Echidna and platypus	Give birth to live, still developing young Examples-Dog and anteater, Echidna and platypus, Opossum and koala	Give birth to live, fully developed young Examples-Opossum and kangaroo, Humans and dogs, Echidna and platypus
Give birth to live, still developing young	Give birth to live, fully developed young	Give birth to live, still developing young
Lay eggs	Lay eggs	Lay eggs

Classification of Mammals

Mammalia is the largest class in the animal kingdom, encompassing various types that can be categorized into smaller, larger, and marine mammals. They are further classified into two subclasses based on their reproduction.

• Eutheria
• Metatheria
• Prototheria

Eutheria

This infraclass includes mammals that give birth to well-developed offspring or deliver them directly. The embryos form within the mother’s stomach, where they undergo a specific period of growth, obtaining nutrition from the mother’s placenta for their development. In total, this infraclass encompasses 19 orders.

Order	Examples
Proboscidea	Elephants
Rodentia	Hamsters, squirrels, Rats
Artiodactyla	Cows
Insectivora	Moles, shrew
Dermoptera	Flying lemurs
Artidactyla	Goat, giraffes, camels
Carnivora	Dogs, Bears
Chiroptera	Bats, flying foxes
Pholiodota	Pangolins
Lagomorpha	Rabbits and hares
Cetacea	Whales, dolphins
Sirenia	Seacows
Perissodactyla	Horses, Zebras
Edentata	Armadillos
Primates	Lemurs, lorises
Afrosoricida	Golden moles
Hyracoidea	Hyraxes
Pilosa	Sloths
Scandentia	Tree shrews

Metatheria

Females in this infraclass are distinguished by the possession of a marsupium or brood pouch, earning them the designation of marsupials or pouched mammals. Immature offspring are born to these mammals and undergo development within their mother’s pouch until reaching maturity. With over 250 species, they inhabit regions across Australia, Papua New Guinea, and certain parts of America. For example, kangaroos, koalas and possums.

Metatheria Sub-class is Divided into 7 Orders Including 250 Species.

Order	Examples
Notoryctemorphia	Marsupial moles
Diprotodontia	Kangaroo
Microbiotheria	Colocolo
Didelphimorphia	New world opossum
Dasyuromorphia	Dasyurids
Peramelemorphia	Bandicoots
Paucituberculata	South American rat opossum

Prototheria

Prototherians, recognized as the most primitive mammals, are exclusively found in Australia and its neighboring islands like Tasmania and New Guinea. Also known as Monotremes, this subclass is characterized by egg-laying mammals, and it encompasses a single order comprising six species. Example: Duck Billed platypus (Ornithorhyncus), Echidna (Tachyglossus).

• Order: Monotremata

General Classification of Mammals

General Classification of Mammals is as follows:

Animals	Lion, Tiger, Dog
Marsupials	Kangaroo, Koala, Womba
Primates	Chimpanzee, Gorilla, Monkey
Rodents	Squirrel. Mouse, Porcupine
Cetaceans	Dolphins, Whales
Other mammals	Seal, Walrus, Sea-lion

Example of Mammals

There are over 5,000 species of mammals on Earth. Mammals are found all over the world, from the coldest Arctic regions to the hottest deserts. They are the most diverse group of animals on Earth. Some examples of mammals include:

1. Humans
2. Dogs
3. Cats
4. Whales
5. Dolphins
6. Bats
7. Elephants
8. Horse,
9. Cows
10. Mice
11. Rats

The largest orders of mammals by number of species are Rodents, Bats, Eulipotyphla, Primates, Even-toed ungulates, Carnivora.

Conclusion – Mammals

Mammals are warm-blooded vertebrate animals with hair or fur, a large brain, and mammary glands that produce milk to feed their young. They are the most dominant form of animals found in almost all types of habitats. Mammals are divided into three groups: monotremes, marsupials, and placentals. Monotremes are mammals that lay eggs, such as the platypus and echidna. 

Marsupials are mammals that carry their young in a pouch, such as kangaroos, koalas, and opossums. Placental mammals are characterized by the presence of a placenta, such as humans, lions, and whales. Mammals are among the most intelligent of all living creatures and they include a wide variety of animals, from cats to humans to whales.

FAQs – Mammals

What is Called a Mammals?

Mammals are a class of warm-blooded vertebrates that have hair, complex brain and produce milk for their young.

What are the 5 Types of Mammals?

Five types of mammals are: Primates-Chimpanzee, Gorilla, Monkey, 2. Rodents-Squirrel, Mouse, Porcupine, 3. Cetaceans Dolphins, Whales, 4. Other mammals- Seal, Walrus, Sea-lion and Animals- Lion, Tiger, Dog.

What are the 7 Characteristics of Mammals?

Mammals are characterized by features such as mammary glands for milk production, warm-blooded metabolism, body hair or fur, live birth, a four-chambered heart, a vertebral column, and the presence of three middle ear bones.

What are the 3 Main Types of Mammals?

Mammals can be generally classified into three broad groups: Eutheria, Metatheria, Prototheria

What are the Major Characteristics of Mammalia?

These creatures are warm-blooded beings adorned with fur, equipped with mammary glands that serve the vital function of nourishing their offspring.

Why is Dolphin a Mammal?

Dolphins are mammals, breathing with lungs, having mammary glands, and giving birth instead of laying eggs.

How are the Mammals Classified?

Mammals are classified as eutheria, prototheria, metatheria.

Give Examples of Prototherians.

Examples of Prototherians include platypus and echidna.

What is the Zoology of Mammals?

Mammalogy in zoology studies mammals, characterized by traits such as homeothermic metabolism, fur, four-chambered hearts, and complex nervous systems.

What’s the Difference Between Wild and Domesticated Mammals?

Wild mammals live independently in natural habitats, while domesticated mammals are selectively bred and live under human care for various purposes.