make up 19 of the 21 different orders of mammals.

3 min read 18-03-2025

make up 19 of the 21 different orders of mammals.

Exploring the Mammalian World: 19 of 21 Orders

Mammals, a diverse and fascinating class of animals, are characterized by features like mammary glands, fur or hair, and three middle ear bones. They're divided into orders, reflecting evolutionary relationships and shared characteristics. While there are 21 recognized orders, this article explores 19 of them, showcasing the incredible variety within this class.

1. Artiodactyla (Even-Toed Ungulates)

This order includes hoofed mammals with an even number of toes, such as deer, cattle, pigs, hippos, and giraffes. They're known for their herbivorous diets and specialized digestive systems.

2. Perissodactyla (Odd-Toed Ungulates)

In contrast to Artiodactyla, Perissodactyla members have an odd number of toes. This order encompasses horses, rhinoceroses, and tapirs. They are also herbivores, but with different digestive adaptations.

3. Primates

Primates, including monkeys, apes, and humans, are characterized by their grasping hands and feet, relatively large brains, and forward-facing eyes. Social behavior and complex communication are also key features.

4. Carnivora

The Carnivora order is easily identifiable – it includes meat-eating mammals like dogs, cats, bears, weasels, and seals. Their sharp teeth and claws are adaptations for hunting and consuming prey.

5. Cetacea

Cetaceans, which comprise whales, dolphins, and porpoises, are fully aquatic mammals. They've evolved streamlined bodies and powerful tails for efficient swimming. Echolocation is a key sensory adaptation.

6. Rodentia

Rodentia, the largest mammalian order, is defined by their constantly growing incisors. Mice, rats, squirrels, beavers, and porcupines are just a few examples of this incredibly diverse group.

7. Lagomorpha

Lagomorphs, including rabbits, hares, and pikas, are herbivores with two pairs of upper incisors. They possess powerful hind legs for leaping and hopping.

8. Pholidota

This order consists of the pangolins, unique mammals covered in scales. They are insectivores with long tongues for capturing ants and termites.

9. Tubulidentata

The aardvark is the sole member of this order. It's a nocturnal insectivore with powerful claws for digging and a long, sticky tongue.

10. Proboscidea

Proboscideans are easily recognized by their trunks. Elephants are the only living members of this order, showcasing remarkable intelligence and social complexity.

11. Sirenia

Manatees and dugongs make up the Sirenia order, completely aquatic herbivores inhabiting coastal waters. They are gentle giants, known for their slow movements and peaceful nature.

12. Hyracoidea

Hyraxes, small herbivorous mammals, resemble rodents but are more closely related to elephants. They live in rocky areas and are known for their social behavior.

13. Macroscelidea

Macroscelides, also known as elephant shrews, are small insectivores with long snouts. Despite their name, they're not closely related to shrews or elephants.

14. Afrosoricida

This order contains tenrecs, otter shrews, and golden moles, mostly found in Africa. They represent a diverse group with unique adaptations to their environments.

15. Insectivora (now split into several orders)

While traditionally a large order, Insectivora has been reclassified into several smaller orders, reflecting a better understanding of their evolutionary relationships. Many of its former members are now included in Afrosoricida and Eulipotyphla.

16. Dermoptera

Colugos, also known as flying lemurs, make up this order. They are gliding mammals with a patagium (skin membrane) stretching between their limbs.

17. Scandentia

Treeshrews, small arboreal mammals, constitute this order. They resemble squirrels but are more closely related to primates.

18. Chiroptera

Bats are the only mammals capable of true flight. They exhibit remarkable diversity in size, diet, and behavior, occupying diverse ecological niches.

19. Didelphimorphia (opossums)

Opossums are the only marsupials found in the Americas. They are known for their prehensile tails and ability to "play dead" as a defense mechanism.

This article only covers 19 of the 21 mammalian orders. The remaining two, Monotremata (echidnas and platypuses) and Peramelemorphia (bandicoots and bilbies), represent unique evolutionary branches within the mammalian lineage, warranting further exploration in a separate discussion. The vast diversity within these orders showcases the remarkable evolutionary success and adaptability of mammals.