Mammals
Definition
● Mammals are vertebrate animals under Class Mammalia.
● They are warm-blooded and have backbones.
● Unique features: mammary glands (milk production) and hair/fur.
● Examples: humans, dogs, cats, elephants, whales, bats.
General Characteristics
● Warm-blooded (endothermic): Maintain body temperature in hot or cold climates. (Example: Polar
bears stay warm in icy regions.)
● Vertebrates: Have a backbone and internal skeleton. (Example: Humans, lions.)
● Hair or fur: Provides insulation, camouflage, and protection. (Example: Tigers have stripes for
camouflage.)
● Mammary glands: Females produce milk to feed young. (Example: A mother cat nursing kittens.)
● Live birth (mostly): Most give birth to live young. Exception: Monotremes lay eggs.
● Specialized teeth: Adapted to diets. (Example: Lions have sharp canines for meat; cows have flat
molars for grass.)
● Diaphragm: Muscle that aids in breathing.
● Well-developed brain: Allows problem-solving and complex behaviors. (Example: Dolphins use
echolocation and problem-solving skills.)
Classification of Mammals
Monotremes (egg-laying mammals):
● Lay eggs instead of giving live birth.
● Found only in Australia and New Guinea.
● Examples: Platypus, Echidna.
Marsupials (pouched mammals):
● Give birth to underdeveloped young.
● Young develop inside the mother’s pouch.
● Examples: Kangaroo, Koala, Opossum, Wombat.
Placentals (largest group):
● Young develop fully inside the womb.
● Nourished through the placenta.
● Examples: Humans, Elephants, Dogs, Cats, Whales, Bats.
Examples of Mammal Orders
● Primates: Humans, monkeys, apes. (Forward-facing eyes, grasping hands.)
● Carnivores: Lions, tigers, wolves, cats, dogs. (Sharp teeth for hunting.)
● Rodents: Rats, mice, squirrels, beavers. (Strong front teeth for gnawing.)
● Cetaceans: Whales, dolphins, porpoises. (Fully aquatic, use blowholes to breathe.)
● Chiroptera: Bats. (Only flying mammals, use echolocation.)
● Ungulates: Hoofed mammals like cows, horses, giraffes, deer.
● Proboscidea: Elephants. (Trunks used for feeding, drinking, and social interactions.)
Importance of Mammals
● Ecological balance:
○ Herbivores (deer, zebras) control plant growth.
○ Carnivores (wolves, tigers) regulate prey populations.
○ Omnivores (bears) help spread seeds.
● Human use:
○ Food (milk, meat, cheese, butter).
○ Clothing (wool from sheep, leather from cows).
○ Labor (horses, oxen, camels for transport and farming).
○ Companionship (dogs, cats as pets).
● Science and medicine:
○ Mice and monkeys used for medical research.
● Environmental indicators:
○ Polar bear decline shows climate change impact.
○ Dolphin health reflects ocean conditions.
Examples of Adaptations
● Aquatic mammals: Whales and dolphins have streamlined bodies and blubber for insulation.
● Flying mammals: Bats have wings and use echolocation to hunt insects in darkness.
● Arctic mammals: Polar bears and seals have thick fur and fat layers to survive freezing temperatures.
● Desert mammals: Camels store fat in humps, conserve water, and have long eyelashes to protect
against sand.
● Specialized feeders: Anteaters have long sticky tongues for ants; elephants use trunks to grasp food.
Behavior and Intelligence
● Many mammals live in social groups:
○ Elephants live in family herds led by a matriarch.
○ Wolves hunt in packs.
● Some show tool use and problem-solving:
○ Chimpanzees use sticks to catch termites.
○ Dolphins use sponges to protect their noses while foraging.
● Communication and emotions:
○ Whales sing songs to communicate.
○ Dogs show loyalty and affection.
Key Facts to Remember
● All mammals have hair and milk glands.
● Not all mammals give live birth—monotremes lay eggs.
● Mammals are found in almost every habitat: land, air, and water.
● Humans are mammals, belonging to the order Primates.
