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A World First - Here in Gibraltar!

Gibraltar leading the way in dolphin research. The first ever case of hybridisation discovered in our waters.


Locally based marine biologist Rocio Espada, a researcher aboard the Dolphin Adventure yellow catamarans, has had her latest scientific research paper published by Plos One, one of the world’s leading scientific journals. Rocio and Dolphin Adventure work in collaboration with the University of Seville promoting responsible dolphin watching and research.


The Bay of Gibraltar is one of the world’s hot spots for dolphins and this article is a study of our local dolphins, in particular one lone female bottlenose dolphin (Tursiops truncates) that lives here in the waters around Gibraltar and her hybrid calf. The female bottlenose dolphin, named Billie, was first sighted by Dolphin Adventure way back in 2006 as a very young calf swimming with a group of common dolphins (Delphinus delphis). Although both species frequent the same areas they do not mix together, they will, in fact, avoid each other. It was realised then that she was going to be very special, but little did we know just how special. Billie has stayed in the bay with the common dolphin, returning year after year, and has in effect been adopted by them. Over the years Billie has been sighted and recorded hundreds of times and in 2016 she was seen holding a new born dolphin to the surface, which is natural behaviour just after a birth. The pair, mother and calf, were studied for 10 months when Rocio Espada, Luisa Haasova and the Dolphin Adventure team gathered behavioural data and photographic evidence. Photographs of the calf have been examined and accepted as proof that it is a hybrid of common and bottlenose dolphins with characteristics of both species present.  The calf had a robust body with length similar to the bottlenose, while its lateral striping and colouration are typical of the common dolphin. It also displayed the common dolphin’s ‘criss-cross’ pattern.


This is the only recorded case of this in the world and is a very important in the world of marine science. This puts Gibraltar firmly on the map for cetacean research and shows that responsible dolphin watching platforms can be used effectively for research.

To read the full article, click here:

Billie Hybrid Grid Pic.jpg

From the photographs we can see (A) muted ‘criss-cross’ pattern typical of common dolphins, photographed 5 November 2016. (B) Creamy yellow patch on its side documented 7 February 2017; (C) light grey posterior flank on 20 February 2017; (D) Striped pattern on 20 February 2017; (E) Comparison between potential hybrid (top right) and common dolphin calf (bottom left). A similar ‘V’ shape and light-coloured dorsal fin can be observed in these dolphins. Documented on 20 February 2017.

Morphological features as coloration and shape patterns of the presumed hybrid.

Extracted from Espada R, Olaya-Ponzone L, Haasova L, Martín E, García-Gómez JC (2019)

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