This collection of mammals photos are added as an aid to identifying mammals you see in your backyard, garden, or neighborhood.

The word mammal comes from the mammary glands which the female of a species makes milk to feed her offspring during their infancy.  There are other characteristics that define mammals. Here are the characteristics.

1. The female mammals nurse their young with milk made in their mammary glands.
2. Mammals have hair or fur.
3. Mammals are warm-blooded.
4. Mammals give birth to live young.

The photos are roughly organized by average size. The smallest mammals are presented first. The larger animals are toward the end of the photo gallery.

Grizzly Bear (Ursus arctos) in Yellowstone Park. Photo by Terry Tollefsbol/US Fish & Wildlife Service.

Gray Wolf (Canis lupus). Photo by NPS.gov/public domain.

Gray Fox (Urocyon cinereoargenteus). Photo by USFWS/public doamin.

Bobcat (Lynx rufus) sitting in a tree. Photo by USFWS/public domain.

White-tailed Deer (Odocoileus virginicus) 51 – 82 inches long.

White-tailed Deer (Odocoileus virginicus) 51 – 82 inches long. Photo by Donna L. Long.

Opossum (Didelphis virginiana) – 24 to 32 inches long. USFWS Refugee Staff/public domain.

North American Porcupine (Erethizon dorsatum) 20-32 inches long. Photo by FWS/public domain.

Beaver (Castor canadensis) 32 – 55 inches long. Photo by NPS.gov/Public domain.

Groundhog or Woodchuck (Marmotoa monax). Photo by Donna L. Long.

Cottontail Rabbit (Syvilagus floridanus) in Fort Washington State Park. Photo by Donna L. Long.

Gray Squirrel (Sciurus carolinensis) eating maple seeds. Photo by Donna L. Long.

Eastern mole (Scalopus aquaticus). Photo by USFWS/public domain.

Little Brown Bat (Myotis lucifugus) Photo by USFWS/public domain.

Chipmunk (Tamias striatus) 8 to 10 inches long. Photo by Donna L. Long.

Deer Mouse (Peromyscus maniculatus). Photo by NPS.gov/Public domain.