Page 142 - A Field Guide to Fairfax County's Plants and Wildlife
P. 142

Mammals are a class of warm-blooded vertebrates. Modern mammals
range in size from tiny mice to enormous whales and are found in nearly
every habitat on Earth: deserts, woodlands, oceans, grasslands, rain
forests, polar regions and many others. Although they look very different,
all species of mammals share some common characteristics:

• All have lungs and breathe air
• All have fur or hair at some point in their lives
• All (except for the platypus and the spiny echidna) give birth to live

young which they nourish with milk produced by the mother

The exact relationships between mammalian groups are not universally
agreed-upon, even today. The scientific classifications of mammals (as well
as other organisms) are constantly being updated by biologists. Below is a
list of the better-known groups of mammals which will give you an idea of
how modern species are related to one another:

• Monotremes - egg-laying mammals like the duck-billed platypus
• Marsupials – pouched animals like opossums and kangaroos
• Insectivores - small insect-eaters like moles, shrews and hedgehogs
• Bats – the only mammals that can truly fly
• Carnivores – meat-eaters such as dogs, cats, bears, Raccoons,

weasels, seals and their kin
• Ungulates – hoofed herbivores like cows, horses and deer
• Cetaceans – whales and dolphins
• Elephants and manatees
• Lagomorphs – rabbits, hares and their kin
• Rodents – mostly small mammals with large front teeth for gnawing;

mice, rats, squirrels, beavers, porcupines and many others
• Primates – lemurs, monkeys, apes and humans

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