Dolphins are a category of about forty species of aquatic mammals. They are highly social creatures known for their mutual aid and empathy not only within their species but with other some other species as well. For example, a group of dolphins in 2004 circled humans off New Zealand’s coast in order to protect the swimmers from a great white shark. A biologist remarked on this incident, “Dolphins are known for helping helpless things. It is an altruistic response and bottlenose dolphins in particular are known for it.” In 2012 or 2013, an adult bottlenose dolphin joined a group of sperm whales off the coast of Portugal: "For eight days, the dolphin traveled, foraged and played with the adult whales and their calves. When it rubbed its body against the whales, they would sometimes even return the gesture."
Known to be extremely intelligent, dolphins communicate with each other with clicks, whistles, and other sounds. The average dolphin lives for twenty-five years, and a dolphin can live for up to forty years.
Dolphins live in a structure called a pod (herd) that usually has about twelve members. From time to time, pods temporarily join together and form a school (superpod) that can occasionally exceed 1,000 members. While there some degree of hierarchy within a pod, it is easy for a dolphin or family of dolphins to leave a selfish leader behind and join a different herd. The website Dolphins World explains, “It seems that dolphins are free spirits. Studying the dynamic of the social composition of the pods, scientists discovered that when dolphins belong to a group, nothing binds them to it in a matter of space and time, this means that they can move freely to different pods that are in their vicinity, then the movement of members is continuous. This type of social network is flat and open.”
The bottlenose dolphin has three basic levels of organization: the group, the pod, and the school. A group has two to five individuals, often a family. Groups join together to form a pod, which has up to fifteen members. Finally, pods sometimes join together into a temporary school, which has as many as thirty members.
A herd can switch between a variety of complex swimming formations while hunting. Scouts will explore an area and let the rest of the herd know if there are fish to eat. On the hunt, a herd rapidly switches between different formations. Searching for food, the whole herd will sometimes stick together, and other times they will split up and search as small groups. Once it is time to catch and eat fish, the dolphins swim in a circle around their prey, forcing the fish into a concentrated mass on which the dolphins have an easy time feasting.
So-called “dominant” dolphins—who are at least sometimes females—have the job of investigating any unknown situation and determining whether or not the environment is safe for the herd.
The dolphins do not just hunt together; they also play together. They playfully jump above the water, they dance, and they chase each other. They also toss around jellyfish and splash each other. Finally, dolphins rub their bodies together and engage playfully during sexual behavior. Dolphins interact sexually for fun, not just for procreation. Homosexual contact is common.
- Lori Gruen, Ethics and Animals: An Introduction (Cambridge: Cambridge University Press, 2011), 1.
- Candice Gaukel Andrews, "Is Animal Altruism Real?," Good Nature Travel, 5 February 2013, https://www.nathab.com/blog/is-animal-altruism-real/.
- “Dolphin,” Wikipedia, accessed 14 June 2018, https://en.wikipedia.org/wiki/Dolphin.
- “How Long do Dolphins Live?”, Dolphins World 2 October 2013, https://www.dolphins-world.com/how-long-do-dolphins-live/.
- “Dolphin Social Structure,” Dolphins World, 26 April 2017, https://www.dolphins-world.com/dolphin-social-structure/.
- V.M. Bel’kovich et al, “Herd Structure, Hunting, and Play: Bottlenose Dolphins in the Black Sea”, in Dolphin Societies: Discoveries and Puzzles ed. Karen Pryor and Kenneth S. Norris (Berkeley: University of California Press, 1991), 19, 24.
- Bel’kovich et al, “Herd Structure,” 20-21, 42-43, 46.
- Bel’kovich et al, “Herd Structure,” 21.
- Bel’kovich et al, “Herd Structure,” 69-71.
- “Dolphin,” Wikipedia.