LESSON 2 - SeaTrek Programs

Lesson 3
The Reel World
Breeding season varies and depends on location. During this time, alliances of males spend much of
their time close to females in estrus, the period of time in which females are able to become pregnant. Bottlenose
dolphins have a promiscuous mating system: males and females may mate with many partners. The
interval between births is typically 3-6 years. However, if a mother loses her calf, she can become pregnant
soon afterwards.
Females reach sexual maturity between 5-12 years old, while males reach sexual maturity around
10 years of age. However, males may not reach social maturity until later, meaning they may not breed until
their late teens.
The gestation, or length of pregnancy, is 12 months. Labor can last from 45 minutes to several hours.
Typically, one calf is born at a time, tail first. At birth, the calf measures 35-45 inches (89-114 centimeters)
in length and weighs 45-55 pounds (20-25 kilograms).
Calves generally stay with their mother for 3-6 years. A mother has two hidden nipples, one on either
side of her genital slit. A calf lives from the mother’s fat-rich milk for at least the first year of life and
may continue to suckle for several years but is usually weaned to a diet of fish within two years.
Dolphins appear to identify each other not by sight, but by using unique whistles called signature
whistles. Each dolphin develops an individual whistle that is exclusive to that animal. Dolphins also communicate
using other sounds and body language, such as burst pulse calls, clicks, and slaps of the tail, head, or
entire body against the surface of the water.
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