Mammals—a group that include humans—are warm-blooded animals with hair and vertebrates, or backbones. Unlike other classes of animals, female mammals produce milk to nourish their young. Almost all mammals give birth to live young (except for the platypus and echidna, which lay eggs).
Scientists have identified more than 5,400 mammal species on Earth, roughly one-fifth of which are known to be threatened or extinct. One of the most threatened order of mammals is the primate, which includes monkeys and apes. The United States has more than 400 mammal species. Of those mammals, nearly a quarter are listed on the U.S. endangered species list for reasons including habitat loss, climate change, pollution, and disease.
Bats
Nocturnal, flying mammals that eat fruits and insects
| Bats | Indiana Bat |
| Jamaican Fruit-Eating Bat | Little Brown Bat |
Rodents
Gnawing mammals with a single pair of incisors
| American Beaver | Black-Tailed Prairie Dog |
| Dusky-Footed Woodrat | Flying Squirrels |
| Pocket Gophers | Red Squirrel |
| Red Tree Vole |
Lagomorphs
Gnawing mammals with two pairs of incisors
| American Pika | Snowshoe Hare |
| Swamp Rabbit |
Moles and Armadillos
Burrowing mammals
| Moles | Nine-Banded Armadillo |
Carnivores
Meat-eating mammals, such as bears, felines, and canines
| Black Bear | Canada Lynx |
| Florida Panther | Gray Wolf |
| Grizzly Bear | Hawaiian Monk Seal |
| Mountain Lion | North American River Otter |
| Polar Bear | Raccoon |
| Red Fox | Red Wolf |
| Wolverine |
Ungulates
Hooved mammals with four legs
| American Bison | Bighorn Sheep |
| Key Deer | Moose |
| Mule Deer | Pronghorn |
Cetaceans and Sirenians
Aquatic mammals with paddle-shaped forelimbs
| Blue Whale | Harbor Porpoise |
| Humpback Whale | Orca |
| Sperm Whale | Spinner Dolphin |
| West Indian Manatee |
Sign Up for Updates
A new storymap connects the dots between extreme weather and climate change and illustrates the harm these disasters inflict on communities and wildlife.
Learn More
Take the Clean Earth Challenge and help make the planet a happier, healthier place.
Learn More
A groundbreaking bipartisan bill aims to address the looming wildlife crisis before it's too late, while creating sorely needed jobs.
Read MoreMore than one-third of U.S. fish and wildlife species are at risk of extinction in the coming decades. We're on the ground in seven regions across the country, collaborating with 52 state and territory affiliates to reverse the crisis and ensure wildlife thrive.
PO Box 1583, Merrifield, VA 22116-1583
800.822.9919
Share
