Mammals - Characteristics and Taxonomy Print Friendly and PDF

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Mammal Classification

Kingdom Animalia
---Phylum Chordata
------Subphylum Vertebrata
---------Class Mammalia

Characteristics of Mammals

  1. Mammary Glands: All mammals possess mammary glands, which produce milk to nourish their young. This distinguishes them from other animals.

  2. Hair or Fur: Mammals have hair or fur covering at least some parts of their bodies at some point in their life cycle. This hair serves various purposes, including insulation, protection, and sensory functions.

  3. Warm-Blooded (Endothermic): Mammals regulate their body temperature internally, maintaining a relatively constant temperature regardless of the external environment. This trait helps them adapt to various climates.

  4. Live Birth: Most mammals give birth to live offspring. The young develop within the mother's body and are nourished through the placenta or milk after birth.

    Monotremes are a group of mammals that lay egg. Marsupials raise young in a pouch.

  5. Diaphragm: Mammals have a diaphragm, a muscular structure separating the chest from the abdominal cavity. This is essential for breathing and helps in the inhalation and exhalation of air.

  6. Specialized Teeth: Mammals have different types of teeth (incisors, canines, premolars, molars) that are adapted to their specific diets, allowing them to chew and process food efficiently.

  7. Large Brain Relative to Body Size: Compared to other vertebrates, mammals generally have larger brains relative to their body size. This often correlates with complex behaviors and cognitive abilities.

  8. Three Middle Ear Bones: Mammals have three middle ear bones (hammer, anvil, and stirrup) that transmit sound vibrations from the eardrum to the inner ear. This arrangement contributes to their acute hearing abilities.

  9. Complex Social Behavior: Many mammals exhibit complex social structures and behaviors, including parental care, communication through vocalizations, and hierarchical societies.

Specialized Teeth

Incisors - biting
Canines - stabbing, holding
molars - crushing, grinding

Different types of mammals have different types of teeth - depending on their diet

Predators have large canines
Herbivores have large flat molars

Mammals have a four chambered heart and a double loop circulatory system

Mammary Glands - used to nurse young, produce milk

Types of Mammals

Monotremes (egg layers), Marsupials (pouch), Placentals (uterus)

Order Monotremata

Egg laying mammals found only in Australia
Have reptilian characteristics (cloaca & egg laying)
Have mammalian features (hair, mammary gland)



Duck-billed platypus lives in Australia, lays eggs and males have a venom gland


The spiny anteater, also known as the echidna

Order Marsupiala

Mammals bear their young in am immature state, babies develop in a pouch
Majority are found on Australia, opossums are found on other continents
Examples: Kangaroo, wallaby, tasmanian devil, koala (click to see pictures)

Placental Mammals

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Alternative: Print out Mammal Orders Chart, fill in information from the presentation

Placental Mammals have a gestation period (length of time in uterus)
Placenta- membrane that allows nutrients to pass thru from mom to baby

Domesticated animals have been kept and bred by people - cows, dogs, pigs, horses..etc

Placental Mammal Orders

Rodentia - teeth specialized for gnawing, incisors grow continuously. Ex. Mouse, rat, beaver

Chiroptera- flying mammals (membrane wing), use echolocation. Ex. bats

Insectivora - mainly eat insects, long noses. Ex. shrew & mole

Carnivora - flesh eating hunters, large canines. Ex. dog, cat, fox, lion, bear, raccoon

( Pinnipedia - marine mammals that mate on land. Ex. Walrus, seal)

Primate - adapted for living in trees, intelligent, opposable thumbs. Ex. Chimpanzees, humans

Artiodactyla - type of ungulate (hoofed mammal), even toed, Ex, sheep, cow. Large rumen in stomach helps break down plant material.

Perissodactyla - type of ungulate, odd toed. Ex. horse, rhino. Plant material is digested in a cecum

Cetacea - marine mammals, use echolocation, have blowhole. Ex. whales & dolphins

Lagomorpha - one pair of long incisors, legs specialized for hopping. Ex. rabbits and hares

Sirenia - marine mammals that live in shallow water. Ex. Manatee & dugong

Proboscidea - named for their trunk, or proboscis, many have long tusks (incisor). Ex. elephants.

Xenarthran - Sloths, anteaters