Dolphins are highly intelligent and can be found all over the world in oceans, rivers and estuaries. As mammals, dolphins don"t have gills so they can"t breathe underwater. They must surface to inhale and exhale stale air, which they do through blowholes and not their mouths. How long they can hold their breath depends on the species; some can go for 3 to 7 minutes, while others can stay submerged for up to 20 minutes. Because they must always surface, half of dolphins" brains are always active, meaning they never completely fall asleep. Despite being able to exist in an array of environments and water temperatures, dolphins are threatened by a variety of human activities, such as hunting, pollution and fishing.
Dolphin pod near Réunion island
Today in History
More Desktop Wallpapers:
-
Gran Paradiso National Park, Italy
-
Cape Breton Highlands, Nova Scotia, Canada
-
Grand Canyon National Park, Arizona, USA
-
Guanacos, Los Glaciares National Park, Argentina
-
Spine-cheeked anemonefish
-
Manatee in Crystal River, Florida, United States
-
Dolmen of Sorginetxe, Spain
-
Least chipmunk
-
Tufa formation on Mono Lake, California, United States
-
Bengal tiger, India
-
Bernina Pass, Graubünden, Switzerland
-
Samuel Beckett Bridge, Dublin, Ireland
-
American bison
-
Ironwood Forest National Monument, Arizona, USA
-
Thousand Islands region, St. Lawrence River, USA-Canada border
-
Walton Lighthouse, Santa Cruz, California, USA
-
Ocean City, Maryland, USA
-
Tombeau du Géant in Bouillon, Belgium
-
Cypress trees in George L. Smith State Park, Georgia, United States
-
Quiver trees, Namibia
-
Greater flamingos at Pont de Gau Ornithological Park, Camargue, France
-
Temple of Philae, Aswan, Egypt
-
Yoho National Park, British Columbia, Canada
-
Toronto, Canada
-
Taktsang Palphug Monastery, Bhutan
-
Arraial do Cabo, Brazil
-
Bardenas Reales Biosphere Reserve and Natural Park, Navarra, Spain
-
Sea otter, Glacier Bay, Alaska
-
Coyote Gulch, Glen Canyon National Recreation Area, Utah, USA
-
Wood duck hen
Bing Wallpaper Gallery


