Mammals: Definition, characteristics, types and examples

What are Mammals? – Mammals are animals that suckle and are animals with the most diverse species on earth. Mammals come in all shapes and sizes. The way of life in the environment and its habitat also varies. All mammals interact with one another.

We, as humans are also mammals, therefore, humans tame other mammal species. Mammals, including humans, are warm-blooded vertebrates. Vertebrates are creatures with backbones and hair.

Mammals feed their young by suckling, in contrast to birds. The mammalian brain is considered more developed than other species. See the article below to find out more about mammals.


Definition of mammals

The word mammal is a creation of Carl Linnaeus. Mammalia comes from the Latin word ‘mamma’ which means nipple. This word was first put forward in 1758. Mammals are known and referred to as mammals because mammals suckle their young.

Mammals have mammary glands as a food source. Most mammals reproduce by giving birth to their young, but there are some mammals that do not give birth, or lay eggs. Mammals of this type, called monotremes, have mammary glands, but no nipples. Therefore, these monotremes are still classified as mammals.

Sinaumed’s can do various interesting facts and fun mammal adventures through the Encyclopedia of the World of Mammals which is below.

Characteristics of Mammals

The following are the characteristics of mammals that distinguish them from other species.

  • have mammary glands.
  • have a backbone (vertebrates).
  • have limbs to move such as swimming, running and holding things.
  • has hair to cover the whole body.
  • have nails or claws on the fingers. these nails or claws are useful for climbing or holding food.
  • They have different types of teeth, canines, incisors and molars.
  • have lungs for breathing.
  • has a heart organ divided into two vestibules and two chambers.
  • most reproduce by giving birth (viviparous) some reproduce by laying eggs (ovoviviparous)
  • has a place to develop the embryo, namely the uterus

Mammals that can live in dry or wet places make them unique and spread all over the earth. Get to know all mammals through the book Encyclopedia Exploring the World of Mammals.

Mammal Animal Anatomy

Mammals can be identified by having sweat glands as well as mammary glands. But there are several other features that are not visible if only examined through fossils. For the most part, the characteristics below were not shared by the mammalian ancestors of the Triassic. The following is the anatomy shared by all mammals:

  • Jaw joint : Most mammals have a mandibular bone that attaches to the bones of the skullcap and forms a joint.
  • Middle ear: Mammals can hear by means of sound which is carried from the eardrum by a chain of three bones, the incus and stapes.
  • Teeth: Mammals have a layer of enamel which is present on the surface of the teeth. The enamel layer is composed of prisms, solid elongated rod-shaped structures.
  • Occipital : Mammals have two knobs at the base of the skull that enter into the uppermost neck. Most other tetrapods have only one.
  • Sexual dimorphism: in most mammals, the males are larger than the females. All mammal males fight over females. Females of larger mammals have lower reproductive rates than smaller ones. This suggests that fecundity selection prefers females that are smaller in most mammals.
  • Biological systems: The majority of mammals have seven vertebrae. All mammalian brains have a neocortex, this area is unique to mammals. Mammalian lungs are shaped like a sponge or honeycomb. The mammalian heart is divided into four chambers, two upper and two lower atria. The heart with four chambers separates and ensures blood can flow in the right direction. The skin of mammals consists of three layers, the epidermis, dermis and hypodermis. The epidermis of the mammalian skin serves as a water-resistant layer.
  • Fur: ​​Mammals have fur, of different shapes and types. Each type of mammalian hair has its own function. Generally, the function of mammalian fur is sensory, camouflage, protection and also waterproofing. Some mammals that live in the tropics have fur the same length as arctic mammals.
  • Reproductive system: Mammals are gonocoric. Gonokoris is giving birth with male or female genitals, in contrast to hermaphrodites. Male mammals have a penis which is used for urination and fertilization. Female mammals have a clitoris, labia majora and labia minora on the outside of their genitals. The mammary glands in female mammals are the main source for newborns. Unlike other species, although some have nipples, unlike mammals they have mammary glands.
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Mammal behavior

1. Communication

Mammals communicate by making sounds. Making this sound also has many meanings such as wanting to mate, warning of danger signs, telling there is a food source and for socialization purposes. For example, male lions who always make noise during mating rituals to drive away other males.

This of course also serves to attract females. The sound of whale songs is also a signal to the females, whales have different dialects depending on the area of ​​the ocean.

Sinaumed’s can learn other interesting facts about whales, such as how whales can spit water from their heads in the book Animal Anatomy Series: Whales and Other Mammals.

These vocalizations also include territorial calls, or distinguish between groups. For example elephants, they communicate socially with various forms of sound such as grunting, sounding a trumpet-like sound, roaring and rumbling. This thunderous call is below the range of human hearing. This sound can only be heard by other elephants, even if they are within a radius of 10 km.

2. Feeding

Mammals need a lot of energy to maintain a constant body temperature, therefore mammals also need nutritious food. Some mammals are meat eaters but some are plant eaters. Plant-eating mammals consume complex carbohydrates such as seeds, leaves, fruit, nectar and also mushrooms.

Apart from carnivores and herbivores, there are also those who eat everything, namely omnivores, they consume both meat and plants. Carnivorous mammals have a simple digestive system. The size of the animal also determines the type of food consumed. Mammals with a small body size require more high energy and have a high metabolism. Meanwhile, larger animals have a slower digestive system.

Some mammals are omnivores, but generally lean towards carnivores or herbivores. Because meat and plants are digested in different ways, there is a preference for one over the other. For example, bears, there are 70% meat eaters, 50% meat eaters and some are less than 50%.

3. Mammal Animal Intelligence

In intelligent mammals, the cerebrum tends to be larger than the rest of the brain. This intelligence is actually not easy to define, but indications of intelligence can include the ability to learn. For example, primates and mice, they can learn and do a new task. This is an important ability when they are first going to a new habitat.

Types of Mammals and Examples of Mammals

Mammals are further divided into several orders which are grouped based on similarities in their characteristics. The following is the order of mammals along with examples.

1. Monotreme

Monotremes are the only mammals that reproduce by laying eggs. The monotremata order in Indonesia is only spread in Papua. The genitals are in the form of a single hole, which is also the digestive tract and the urinary tract.

For male monotremes, the tip of the penis is boneless. Female monotremes do not have nipples, but they do have mammary glands. Milk will be channeled through the hairs on the female stomach. Examples of short-snouted nokdiak monotremes, nokdiak baliem and nokdiak sentani.

2. Dasyuromorphia

Dasyuromorphia is a marsupial that has many incisors. These carnivorous marsupials are more active at night. This four-legged mammal has a hairy tail and a pointed muzzle.

Marsupials have large skulls and tails shorter than body length. They had soft leather pads all the way to the heel on the soles of their feet. These pads are useful for supporting their bodies when standing and walking. An example of Dasyuromorphia is the extinct sarcophilus laniarius or the Tasmanian devil.

3. Peramelemorphia

Peramelemorphia is an animal that has a pouch. They have a long, pointed nose, a short neck, and a long canal-like pouch that connects the uterus and embryo. They have four legs and are stocky.

Some species of Peramelemorphia have ears that resemble those of a rabbit. These nocturnal animals have good eyesight and sense of smell. Peramelemorphia is an all-eating or omnivorous mammal. They usually eat insects, leaves or tubers. Examples of Peramelemorphia are Bandikut rats and Kalubu esut.

4. Diprothodontia

Diprotodontia are the most diverse group of marsupials with a very large number. Nearly 125 species in the world are included in the Diprotodontia group. This group is arboreal, they walk on two legs and have special behaviors such as being able to jump far or dig holes for their homes.

Another distinctive feature of them is that their hind toes are fully fused. Most of them are herbivores, but there are also some of them that are omnivores. Examples of Diprotodontia are artifact hook-tailed possums, bubutu talaud and kangaroos.

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5. Eulipotyphla

Eulipotyphla is a mammal that eats insects. Although they are insectivorous, their bodies weigh less than 20g. Eulipotyphla lived on land, had a rat-like body with a long, pointed snout.

Their snouts and the hair around them become sensory tools as navigation for their movements in hunting for their prey. They have sharp and pointy teeth. These sharp teeth serve to chew and stab their prey. They also have incisors which are very well suited for grasping. Examples of Eulipotyphla are curut thick tail, curut cibodas, and house munggis.

6. Scaling

Scandentia is a mammal that eats insects, fruit and seeds. Their body is similar to that of a squirrel, but they have a long, pointed snout. Scandentia tend to have a small body, flat and elongated body, also a tail with thick hair.

This four-legged animal has fine body hair and sharp claws. Scandentia is a group of animals that have good hearing. There are animals that are more active during the day that live in groups, pairs or colonies. They live in trees and move from branch to branch. Examples of Scandentia animals are root squirrels and ground squirrels.

7. Dermoptera

Dermaptera are mammals that have mucous membranes that run all over their bodies. This kite membrane in the form of thin skin is found on the neck to the tip of the tail. This kite membrane is covered with thin hairs with a grayish brown color.

The front and hind legs have sharp claws. These claws are useful for holding and gripping tree branches. They have very small teeth, incisors that are similar to a comb used for feeding their children and grooming to keep their bodies clean. Dermoptera have sharp fangs and wide molars. These nocturnal animals consume fruits, young leaves and flowers. Examples of dermoptera animals are G. variegatus and G. volans.

8. Chiroptera

Chiroptera are mammals that can fly. Its fingers can expand to become wings. Chiroptera wings have a thin, elastic skin-like covering. These nocturnal animals are divided into two, namely fruit-eating bats and insect-eating bats.

Generally, fruit-eating bats have a larger body size than insect-eating bats. The eyes are also large and some of them have claws on their fingers. Fruit-eating bats have a very keen sense of smell and sight. This is useful to help them aim at the fruits.

Meanwhile, insect-eating bats search for food using ultrasonic waves that cannot be heard by humans. Examples of chiroptera, black trubus bats and bats.

Various other examples of mammals that exist in the world today are also mentioned in the book Mammalia 1 – Exploring the Animal World.

9. Primates

Primates are mammals that have a placenta. Indonesia has 62 species of primates, most of which live in tropical forests. The sizes of primates vary greatly. There are very small ones weighing 30 g and the largest 175 kg, namely gorillas.

Primates have hair that covers their entire body. They have a straight posture and the ability to learn. Hands and feet have fingers that can grip objects. The braincase of primates is relatively large. Many call primates monkeys and apes, but there are differences between them. Examples of primates are macaque monkeys, langurs, slow lorises, and budeng langurs.

10. Carnivores

Carnivores are a group of mammals that eat meat, but a small number of them eat everything and plants. For example the panda, a bamboo-eating animal. Carnivores have canine teeth and claws, walk on all four legs and have whiskers. Examples of carnivores are tigers, dogs, sun bears and starfish.

11. Cetacea

Cetacea are a group of marine mammals. There are whales, dolphins and dolphins. 34 species of cetaceans are in Indonesian waters. Cetaceans have a body shaped like a torpedo. They have strong horizontal fins for locomotion, in contrast to the vertical fins of fish.

They also have nostrils which act as blowers. This hole has a function for their breathing apparatus when they are in the water. Examples of cetaceans are toothed whales, baleen whales, blue whales and long-beaked dolphins.

12. Mermaid

Sirenia is a group of mammals that live in water, similar to cetaceans. Sirenia is a plant eater that spreads in tropical waters. These aquatic animals have nipples on their chests, they breastfeed their children by turning their bodies so that their chests are up.

Sirenia has a rounded tail tip and some are straight or curved inward. One example of Sirenia is the dugong.