14 Interesting Facts about Mammals

When was the First Mammal Seen? What are Various Facts Related to them? Why are Humans called Mammals?
interesting facts about mammals

Animals have been divided into 6 distinct groups depending upon their habitat, namely amphibians, birds, fish, invertebrates, mammals, and reptiles. Today I am going to pick up the mammals animals list and tell you about the reason why are mammals mammals. You will also get to know interesting facts about mammals and the reason why are human beings mammals.

Origin of the First Mammal

According to the researchers, the first mammals may have appeared in the late Triassic period somewhere 225 million years ago. Mammalia, the scientific name, is derived from the Latin word mamma. Carl Linnaeus specified this name in 1758. (See What Was Before Dinosaurs?)

Why are Mammals Mammals?

Sheep in the field with her babies.

The reasons behind them being named mammals are as follows:

  • The presence of the mammary glands (breasts) that produces milk with which they feed and nourish their children.
  • The presence of the Neocortex, a part of the cerebral cortex in the brain. Higher cognitive functions arise from this part.
  • The presence of hair or fur on the whole body is also one of the reasons.
  • They also have three middle bones in the ears. (Also read Do Sheep Sleep?)

14 Interesting Facts about Mammals

Being the world’s largest animal category, there are lots of interesting facts. Mammals are found on land, underwater, on trees, and below ground also. They are capable of surviving in all types of climates depending upon their habitat. (See 5 Name of Mammals that Lay Egg)

1. Have Warmblood

A cheetah looking behind: interesting facts about mammals 5

All mammals, including humans, have warm blood. Most mammals are endothermic because their body temperature remains constant for almost their entire life. All mammals have a backbone (spinal cord), hence termed vertebrates. (See Where are Leeches found?)

2. Have No Nucleus

Single-horned rhino.

The mature red blood cells known as erythrocytes present in mammals lack a nucleus. It is a unique feature that distinguishes them from other vertebrates. (See: What Does It Mean When Your Blood Is Dark Red?)

3. Have Fur on Bodies

A penguin at the beach: interesting facts about mammals 6

A majority of mammals have fur or hairs on their body. Their bodies are covered in thick fur to protect them from the harsh cold weather. For example, Arctic wolf, polar bear, Siberian tiger, etc. Some mammals, like humans and primates, also have a layer of hair on the entire body, but not a thick layer. (See Do Penguins Have Knees?)

4. Have a Three-boned Ear

It is a distinct feature of mammals that the inner part of their ears has three small bones, namely, the incus, malleus, and stapes. Malleus is hammer-shaped and connects the inner surface of the eardrum with the incus. It is anvil-shaped and transmits sounds and vibrations. Stapes is a stirrup-shaped bone and is the smallest of the three bones. (See Do Bees Have Ears?)

5. Have a Left Aortic Arch

A group of antelopes.

Another interesting fact about mammals is that they are the only organism with a left aortic arch. The left pharyngeal artery (fourth) is commonly known as the aortic arch. It is very rare for a mammal to have a right aortic arch, but it is an exception. (See 4 No Stripe Zebra Facts)

6. Have Milk Production and Birth Process

A brown-white cow: interesting facts about mammals 4

The milk is produced in mammary glands and the young ones feed on it till a particular age to become strong. The process of birth in mammals is characterized by 3 categories of marsupials, monotremes, and placental. But in general, the vast majority of mammals are viviparous. It means they give birth to babies and not eggs. (See How To Tip A Cow?)

7. Have a Diaphragm

Mammals also have a diaphragm which is located under the lungs and supports the breathing process. Other animals do not possess these two characteristics. (See 8 Tame Wolf Facts)

8. Have Jaw Connected to the Skull

Attacking crocodile

Mammals are the only vertebrates whose lower jaw is hinged and connected directly with the skull. Therefore, they are capable of grasping, chewing, and grinding food easily. (See How to Describe Crocodile?)

9. Types of Mammals according to their Reproducing Process

Can Elephants have Twins

Mammals are classified into three categories based on their reproduction process. Marsupials, Monotremes, and Placentals are three categories of mammals.

  • Marsupials give birth to babies early and their remaining growth is done in the external pouches of the females. For example Kangaroos.
  • Monotremes lay eggs, but females feed their young ones with their milk. For example Platypus and the spiny anteater. (See What are Baby Platypus Called?)
  • Placental mammals have a reproduction system in which the baby grows in the mother’s womb for a specific time and is nourished through the umbilical cord.

One of the interesting facts about mammals is that the gestation periods of different mammals are not the same. For example, humans, monkeys, elephants, etc. (See What Animal has the Longest Pregnancy?)

10. Species and Orders of Mammals

A group of horses in the stable.

According to the list issued by the Mammal Diversity Database (MDD), there have been 6495 valid species of mammals. Out of these, 96 species have gone extinct, and 6399 species are extant (still existing).

There are 13 to 17 different biological orders in which mammals are classified. These are Artiodactyla, Carnivora, Cetacea, Chiroptera, Insectivora, Lagomorpha, Perissodactyla, Pholidota, Primates, Proboscidea, Rodentia, Scandentia, and Sirenia. (See Do Animals Sweat?)

11. Mammals Animals List (A to C)


  • Artiodactyla includes boars, chevrotains, deer, muntjac, stag, hogs, musk deer, yaks, bucks, buffalo, gazelle, chital, sambar, antelope, goral, and tahr.
  • Carnivora includes jackals, fox, wolf, cheetah, caracal, lynx, wildcat, jungle cat, leopard, marbled cat, lion, leopard cat, rusty-spotted cat, fishing cat, snow leopard, Bengal tiger, civet, linsang, bears, red panda, otters, badgers, marten, weasel, stoat, polecat, mongooses, and hyenas.
  • Cetacea includes dolphins, whales, river dolphins, and porpoises.
  • Chiroptera includes different varieties of bats like fruit, sheath-tailed, mouse-tailed, false vampire, horseshoe, leaf-nosed, evening, and free-tailed bats. (See Why Are Cats Tongue So Rough?)

12. Mammals Animals List (I to L)

adorable golden possum

13. Mammals Animals List (P) 


  • Perissodactyla includes odd-toed ungulates like ass and rhinoceros.
  • Pholidota includes Indian and Chinese pangolins.
  • Primates include lorises, macaque monkeys, langurs, phayre monkeys, and gibbons.
  • Proboscidea includes Indian elephants. (See What is the Difference between Apes and Monkeys?)

14. Mammals Animals List (R and S)

Two beavers in the hole.

  • Rodentia includes squirrels (flying, long-nosed, red-cheeked, palm, marmot, giant flying, giant, and stripped), mice, rats, jird, hamster, gerbil, bush rat, dormouse, vole, bamboo rat, and porcupines.
  • Scandentia includes tree shrews (Madras, Tupaia, and Northern).
  • Sirenia includes a Dugong, which is a type of manatee. (See What Does a Rabbit Symbolize?)

Are Human Beings Mammals?

interesting facts about mammals 2

Humans are considered primates. Primates include monkeys, chimpanzees, lemurs, lorises, and tarsiers. According to the researchers, humans have the same ancestors as chimpanzees but around 8 to 6 million ago they both diverged. Humans also have all the characteristics found in mammals. (See How many Types of Cells are There in The Human Body?)

More Random Interesting Facts about Mammals

  • Anteaters are the only mammals without teeth. (See Do Anteaters Eat Ants?)
  • Only bats among mammals can fly.
  • Cheetahs are the fastest mammal.
  • Orca whales are among the deadliest mammals.
  • Koalas are the longest sleeping mammal, sleeping for about 22 hours a day, yet another of the interesting facts about mammals.
  • Babies of dolphins and whales do not sleep during the first month after their birth.
  • Mammals are social animals. They have strong affection towards their family and kids. They are highly adaptive. (See 7 Chupacabra Animal Facts)
  •  Some mammals have scaly or spiny skin.
  • The skin of a tiger is in the same pattern as its fur.
  • Cats use 16 types of cat words for communication.
  • The shape of the ears of African elephants is similar to the shape of the continent.
  • Kangaroos cannot hop backward.
  • A hippopotamus is considered to be more dangerous than a lion.
  • Cheetahs are capable of changing their direction in mid-air while they are chasing their prey. 

So, these are the interesting facts about mammals and the mammals animals list. You also got to know about why are mammals mammals and are human beings mammals along with the reason for that. (See 12 Catfish Whiskers Facts)

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