In the Bahamas, Denise Herzing and other researchers spend part of every other year with some 50 Atlantic spotted dolphins. Underwater viewing with video cameras allows them to identify individuals by examining the dorsal fin, fluke marks and "constellations" of spots. Researchers can estimate ages by observing the size of the dolphin and the patterns on its body. These change from two-toned in calves to speckled in juveniles, mottled in young adults and fused, or fully spotted, in older adults. Researchers can tell their sex and determine which females are pregnant by looking for a slight bulge in the midsection.

Through such studies, we have discovered that the dolphins form long-term bonds and learn, as young calves, by doing things with their mothers and other dolphins. A calf nurses for up to three years, although it practises chasing and catching bottom fish before 6 months of age. At 3 to 5 years, it leaves its mother when she gives birth to another calf. The juvenile joins a group of the same sex for four or five years. These juveniles, sometimes supervised by an adult, go on hunting expeditions but typically stay on the sidelines, watching. A youngster occasionally returns to its mother to interact with her and her new calf. the females mature at age 6 or more, the males at about age 15.

Stenella frontalis
Size: 1.8 to 2.2 m, 110 kg
Calves at birth: 88 to 120 cm
Teeth: 29 to 34 small, sharp-pointed teeth on each side of upper jaw, 33 to 36 teeth on each side of lower jaw
Food: Various small fish species and squid
Habitat: Mainly offshore waters, sometimes coastal
Range: Tropical, subtropical and warm temperate Atlantic
Status: Population unknown

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