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Spotted Dolphin Adaptations

The behavior and appearance of the two species of spotted dolphin, the Atlantic spotted dolphin and the pantropical spotted dolphin, are well suited to their open ocean environment. Spotted dolphins also have the ability to adapt to changes in their environment, including those caused by human activity, through altering their behavior and breeding strategies. Notwithstanding their adaptability and intelligence, spotted dolphins can only cope with so much. Large-scale hunting operations and accidental deaths in tuna nets are a serious threat to their survival.

Coloring
- The coloring of spotted dolphins changes throughout their lives. Babies and juveniles have no spots. They have dark backs and light bellies, a common pattern in oceanic animals. The reason for this is to make the animal inconspicuous to both predators and prey. When viewed from above, a dark back blends into the darker ocean depths. However, when viewed from below, the white belly is inconspicuous against the light surface. Adolescent dolphins develop the distinctive spots, and show more and more spots as they age. The purpose of these spots is uncertain. It is not a coloring seen in many other mammals and presumably has a social purpose, rather than being purely for camouflage.
Diet
- Spotted dolphins eat a variety of fish and squid. For unknown reasons, in the eastern Pacific, the pregnant females eat mostly squid and nursing mothers mostly fish, according to the American Cetacean Society. This might be because of different nutrients in the foods, because different hunting techniques are required or a "cultural" adaptation that has no obvious biological purpose but is something this population has learned to do, perhaps because of an unusual situation in the past.
Breeding
- Normally, spotted dolphins mature and start breeding between the ages of 6 and 12 years old. Females then have a calf about once every two years. However, because of the numbers of dolphins caught accidentally in tuna fishing operations, spotted dolphins have started breeding earlier and more often. This adaptation is a biological attempt to offset so many of them dying.
Social Behavior
- Spotted dolphins are highly gregarious. They swim together in large groups, which sometimes number thousands of individuals. They also associate with other species, including spinner dolphins and tuna. Aside from the opportunities for socializing and courtship, such large groups of animals provide mutual protection from predators and may assist each other with finding food. Spotted dolphins communicate with one another through clicks and whistles. They also use clicks for echolocation, which allows them to navigate in the low visibility of water.

Animals & Science