Dear Marmamers!

During the 2009 field season off La Gomera we encountered a large number of Atlantic spotted dolphins (Stenella frontalis), a species present year-round in the Canary Islands. In one of the groups, containing a large number of calves, we observed a young animal showing an extrordinarily swollen genital area. The reasons for this phenomenon remain unknown. Luckily, we managed to photograph the animal during aerial behaviours. The according images can be seen at our website:
http://www.m-e-e-r.de/index.php?id=458&L=2

The calf was sighted early May 2009. It obviously was a female, recognisable by the very visible nipples next to the genital slit. The prominent swelling, however, was extraordinary. As the swellling affected the genital area, and no injury could be seen, we initially suspected a hormonal reason. And even if this was true, the question would remain why a young calf showed this feature.
Denise Herzing, working with Stenella frontalis in the Bahamas, was so kind to provode images of a normal female adult dolphin during lactation as a comparison. These images also can be seen at our website.

With this we would like to ask our cetologist colleagues, if anyone has seen something similar before, either in this or in a different species. Also we would like to know the (potential) reasons for this unusual symptom. Does anyone have an idea?

Any helpful information or comments should be directed to <ritter@m-e-e-r.de>

With my best greetings,
Fabian