08 July 2013

Neither striped nor common: intermediate

This beautiful calf photographed in the Gulf of Corinth is likely the offspring of a striped dolphin Stenella coeruleoalba and a short-beaked common dolphin Delphinus delphis – as suggested by the intermediate pigmentation pattern.

Although striped and common dolphins belong to different genera, they can mate and reproduce when they live in mixed groups, as they do in the Gulf of Corinth. We suspect that these hybrids are, in turn, able to produce viable offspring.

Because common dolphins are scarce (about 30 individuals estimated in 2009*) and striped dolphins abundant (about 800-900 estimated in 2009*), interbreeding will likely result in a "dilution" of common dolphin genes into the much larger gene pool of striped dolphins.

We are currently testing the hypothesis that "pure" common dolphins may vanish over time, and be progressively replaced by hybrids like the one above.

(Photo by S. Bonizzoni, July 2013)

* Bearzi G., Bonizzoni S., Agazzi S., Gonzalvo J., Currey R.J.C. 2011. Striped dolphins and short-beaked common dolphins in the Gulf of Corinth, Greece: abundance estimates from dorsal fin photographs. Marine Mammal Science 27(3):E165–E184. 

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