Whales' methods of communication are complicated, and not yet well understood by scientists. Listen to examples of the vast differences in sounds that whales produce in these five recordings of whale vocalizations.
Recording 1: A humpback whale recorded March 22, 2003 at Isla Socorro, Revillagigedo Archipelago, Mexico. Credit: Danielle Cholewiak, PhD., Acoustic Specialist, Stellwagen Bank National Marine Sanctuary. NOAA/NOS
Recording 2: A humpback whale. Credit: Sofie Ban Parijs, Northeast Fisheries Science Center, NOAA Fisheries Service.
Recording 3: A sperm whale echolocating. Courtesy of the Scripps Whale Scoustic Laboratory.
Recording 4: A right whale. Courtesy of the Scripps Whale Scoustic Laboratory.
Recording 5: Another right whale. Courtesy of the Scripps Whale Scoustic Laboratory.
President Theodore Roosevelt was caught in the middle of the first major battle for wilderness preservation in Yosemite National Park.
When an earthen dam broke without warning, a small city in Pennsylvania was swept away in a wall of water over 30 feet high.
John Wesley Powell's epic journey into the unknown Grand Canyon was filled with adventure as his team mapped the Colorado River for the first time.
High on a granite cliff in South Dakota's Black Hills tower the huge carved faces of four American presidents: George Washington, Thomas Jefferson, Abraham Lincoln, and Theodore Roosevelt.
The American effort to relieve starvation in Soviet Russia in 1921 during the worst natural disaster in Europe in 500 years.
The most daring and innovative accomplishment at the turn of the 20th century.
The journey of Prince Maximilian, German naturalist, and artist Karl Bodmer, who explored the Mississippi River area from 1832-1834.
In 1934, American polar explorer Richard Byrd became the first to experience winter in Antarctica's interior.