Mammalia - Definition, Characteristics, Classification, Examples, and Facts Of Mammals

Mammalia, a diverse and advanced class in the animal kingdom, includes warm-blooded vertebrates characterized by the presence of mammary glands, which females use to nurse their young. Mammals have hair or fur, a four-chambered heart, and a well-developed nervous system. In this article, the characteristics of Mammalia, classification, evolution and adaptations are discussed. Mammalia is a topic of the chapter Animal Kingdom in Biology.

Latest: NEET 2024 Paper Analysis and Answer Key 

Don't Miss: Most scoring concepts for NEET | NEET papers with solutions

New: NEET Syllabus 2025 for Physics, Chemistry, Biology

NEET Important PYQ & Solutions: Physics | Chemistry | Biology | NEET PYQ's (2015-24)

This Story also Contains

1. What are Mammalia?
2. General Characteristics of Mammalia
3. Mammals Examples
4. Classification of Mammals
5. Adaptations for Survival
6. Evolutionary Advantages
7. Recommended Video On Class Mammalia

What are Mammalia?

Mammalia, better known today as mammals, is a class of animals with certain features in common like in females, the thread-like ducts called the mammary gland where the young are breastfed, and body covering in the form of hair or fur. Mammals are rather valuable in the animals’ world as they perform certain duties of the top predators, herbivores as well as omnivores all of which play an essential role in the uninterrupted flow of different existing cycles within the ecosystems.

This vast category has more than 6000 species starting with shrews that are small in size and reaching the blue whale, a mammal of a large size, which may live in any geographical area from the hot desert to tropical forests or the ocean depths. These factors of flexibility in their life patterns, detailed and diverse activities, and organization of societies have largely contributed to the success of evolution as well as their importance in ecosystems.

General Characteristics of Mammalia

The characteristics of mammals are listed below-

Hair and Fur

Structure and Function: Hair is made of keratin and has uses for providing warmth/thermal insulation, sparing hardware, as receptors for senses, and as stalks for signalling.

Adaptations and Variations: Fur and skin hair can vary among mammals with thick full hair for insulation, such as the polar bear, or thin for cooling like that on an elephant.

Mammary Glands

Purpose and Evolution: The female reproductive glands termed mammary glands produce milk which is nutritious and contains antibodies for the young ones. They are derived from sweat glands and are significant for the young’s survival.

Endothermy

Regulation of Body Temperature: Mammals for instance are warm-blooded animals and can produce metabolic heat to maintain the body temperature.

Energy Requirements: This endothermy entails a high metabolic rate and a relatively large amount of food consumed as a means of energy.

Specialised Teeth

Types: There are incisors which are sharp for biting food and cutting, there are canines used in tearing food and there are premolars and molars used differently in crushing food.

Adaptations for Diet Diversity: Such teeth help mammals in the view of using almost any type of food as a source of nutrition – from plants to other animals.

Also Read-

• MCQ on Mammalia
• Animal Kingdom
• Phylum Platyhelminthes
• Phylum Ctenophora

Mammals Examples

Classification of Mammals

The classification of mammalia is described below-

Subclasses

Prototheria: This subclass includes egg-laying mammals, which come under monotremes, the platypus and the echidna. They are characterized by their form of reproduction, which is by laying eggs as opposed to the birth of their young ones.

Metatheria: This subclass consists of Marsupials which are animals that give birth to naked, immature young that can develop further outside the womb. Such examples include; Kangaroos, koalas, and opossums.

Eutheria: This subclass is also referred to as the placental mammals and this subsumes the most number of mammals. They bear young and have a very developed placenta through which the fetus is fed. Some examples include persons, elephants, and whales.

Subclass of Mammalia

Orders

Primates: This order consists of lemurs, monkeys, apes and kings of the jungle, man. Some aspects that define the primates include large brain size, forward-facing eyes and a grasping ability provided by the opposable thumb useful in complex conducts and social organisms.

Carnivora: This order of animals includes cats, which are part carnivorous, therefore animals within this order include lions, bears and wolves. It has a built-in melting cat mouth with proper-sized teeth and claws suitable for breaking and eating raw flesh.

Rodentia: This is one of the biggest orders of animals belonging to the mammal category which comprises the murine such as mice, rats and squirrels. Some of the rodents have sharp incisors that grow throughout the animal’s life and they serve the purpose of a scissor, with which the animal will nibble on everything that comes in its way. They have a very important place in ecosystems because they are seeds’ carriers and food for many species.

General Classification of Mammals

The classification of mammals is tabulated as follows-

Adaptations for Survival

The adaptations are listed below-

Reproduction

• Viviparity: It gives protection and comparatively safer habitat for the developing embryo.

• Oviparity: While marsupials (Metatheria) give birth to live young which are usually in a very immature state marsupials (Prototheria) lay eggs (oviparous). This is perhaps a more crude mode of reproduction and comes with the bonus of less energy being used up during pregnancy.

• Mammals take a huge time in caring for their young which may involve feeding, cleaning and even defending the young ones.

• This is a feature that ranges from occurrence in the marsupials, which have their offspring in a pouch to the occurrence in the primates that would support another kind of offspring and also teach them for some time.

Senses and Communication

• Hearing: Most mammals are known to be sensitive to sounds and some of them can make sounds to locate their prey or even to move around in the dark through sonar-like systems (like the use of echolocation by bats or dolphins).

• Vision: Some mammals are almost blind while others are very well endowed; for example, primates have good binocular vision being able to judge distance well because a lot of their lives are spent in trees.

• Olfaction: A quite important sensory organ is the olfactory organ for many mammals it acts to find food, and sense danger, using hormone signals.

Evolutionary Advantages

Higher senses increase the chances of survival because they help in getting to and escaping from potential enemies and social relationships.

Locomotion

• Terrestrial: To move on the land, mammals have the following methods: digitigrade, when the animal walks on its toes, for example, the dog; plantigrade, in which an animal walks on the entire foot like a man; and unguligrade, in which the animal moves on hooves, for instance, the horse.

• Aquatic: For instance, marine mammals, whales and seals have flipper-like limbs and slippery bodies suitable for water.

• Aerial: Bats which are the only true flying mammals, are characterized by a wing, which is a membrane that is stretched between elongated fingers.

Limb Structure and Movement Efficiency

The mammalian limb is a part of the locomotion system, which is well developed according to the prevailing environment with changes in the bone as well as muscle to be effective in running, climbing, swimming or flying.

Also Read-

Recommended Video On Class Mammalia