Life History & Reproduction

When discussing the developmental lifespan milestones of the Common Dolphin, variances can be seen between population zones across the globe. Examples of these populations include the dolphins of the eastern tropical Pacific and the dolphins of the North Pacific. These variations show that there is a connection between geographic location and specific environmental influences that interfere with the overall life cycle of the Common dolphin species. That being apparent, it is most likely that the highlights of the dolphin’s natural life are tending to be influenced in some way by the natural environment around them. (Chivers et al. 2007)

The average length of a newborn varies between geographic locations. The smallest projected length of newborn dolphins originated from the North Pacific (82cm or 2.7ft), while the largest projected length was found in the Eastern North Atlantic region (104.1cm or 3.4ft). (Chivers et al. 2007)

 

In Washington D.C. at Georgetown University, scientists studied the behavioral development of mother-calf relationships in free-range Bottlenose Dolphins (close relatives of the Common Dolphin). It was observed that newborns, immediately following birth, coordinate their swimming and breathing to match that of their mothers. Over time a maturating calf will noticeably change in many ways regarding its behavior near its parent; the mother in turn does not become less nurturing, but still continues to stay near its baby. An example of this seen among dolphin groups includes the shift of an infant’s swimming pattern from early ‘echelon swimming’ to later ‘infant-positioning’ swimming. In other words, over time instead of a baby calf swimming adjacent beside its mother, it will switch to swimming more often underneath its mother as it matures, all the while staying in contact with her. After its first month, a calf will start to ‘practice forage’, socialize independently with other animals, and leave its mother’s comfort zone more often to explore and play in its marine habitat on its own. (Mann et al. 1999)

A dolphin’s sexual maturity differs between environments for the same reasons as their newborn’s lengths do. The lowest age for sexual maturity in the Common Dolphin was found in the North Pacific (8 years old). In contrast, the higher age of the beginning of sexual maturity was found in the Eastern North Atlantic (9 to 10 years old). Along with sexual maturity, the length at sexual maturity and the total longevity of the animal vary as well. (Chivers et al. 2007)

To look at what other organisms interact with the common dolphin go to Interactions

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