Allie, a 26-year-old bottlenose dolphin, swims with her female calf born on August 2 at the Brookfield Zoo in Brookfield, Ill., Aug. 4, 2013. Jim Schulz/Chicago Zoological Society/Reuters
Spinner dolphins are seen near Keahole Point, Hawaii. More people and more activity in Hawaii waters means more impact on ocean creatures, and the entertaining spinner dolphins may be the most stressed. Dolphins constantly performing for tourists can suffer disruption in their eating and reproduction habits and become more vulnerable to predators, according to Steve Soto-Amundson of the South Kona Preservation Coalition. James L. Wing/dolphindreams.com/AP
A pod of Dolphins swims off the coast of Dana Point, Calif., Jan. 6, 2013. Captain Dave Anderson of Captain Dave's Dolphin and Whale Safari said hundreds of dolphins were seen churning up the waters off the California coast about 60 miles (100 km) south of Los Angeles. Captain Dave's Dolphin and Whale Safari/AP
An erect-crested penguin watches as Richard Tesore, head of the NGO Rescate Fauna Marina, holds a baby La Plata river dolphin in Piriapolis, 100 km (62 miles) east of Montevideo, November 5, 2010. The dolphin, which was found on the beach in the city recovered at the reserve from injuries believed to have been caused by a fishing net. Andres Stapff/Reuters
Using a sling, Linda D'eri (l.) and Misty Niemeyer, members of an International Fund for Animal Welfare rescue team, carry one of 11 dolphins stranded on a mud flat during low tide in Wellfleet, Mass., Feb. 14, 2012. Ten of the dolphins were saved and one perished during the event. Stephan Savoia/AP
Indonesian activists hold anti-dolphin hunting posters during a protest in front of the Governor's office in Danpasar, Bali, Indonesia, Dec. 7, 2012. Firdia Lisnawati/AP
This aerial view shows about 800 Hong Kong schoolchildren and teachers from 14 schools, and volunteers gather to form an image of the Chinese white dolphin with the Chinese characters "Ocean" on the Repulse Bay Beach in Hong Kong Nov. 9, 2012. Kin Cheung/AP
Catherine Dunn (c.) a trainer at the Florida Keys-based Dolphin Research Center, shows Delta the dolphin to Josh Wetzel (l.) and British Army veteran Steve Gill (r.) in Marathon, Fla., Jan. 11, 2013. The opportunity to interact with the marine mammal was a facet of Soldier Ride, a bicycle journey staged by the Wounded Warrior Project to help restore injured soldiers' physical and emotional well-being. Andy NewmanFlorida Keys News Bureau/AP
A Beijing resident enjoys his coffee at an American cafe under a display of giant models of dolphins and coral fish April 30, 2001. More and more foreign coffee shops have opened in the city where residents, traditionally tea drinkers, have developed a taste for coffee. Reuters
A worker of Cuba's National Aquarium performs with dolphins in Havana, Cuba, July 5, 2011. Since its opening in 1960 Cuba's National Aquarium promotes educational activities aiming to widespread knowledge about the sea and its resources. Javier Galeano/AP
For years, biologists have argued over the number of species of humpback dolphins. Recent research somewhat settles the debate, as a team of biologists have discovered at least four distinct species – one of which had previously gone unnoticed.
Amelia Pak-Harvey, Contributor /
October 30, 2013
Jonathan Hayward/The Canadian Press/AP
Humpback dolphins have the scientific community stumped.