Friday, September 16, 2011

An interesting morning with big groups of bottlenose dolphins, Atlantic spotted dolphins and Risso's dolphins to observe! The Risso's dolphins were especially interesting as they were repeatedly jumping and tailslapping.. perhaps some examples of the aggressive behaviour between individuals which results in the scratches and scarring on adult Rissos. These scars are thought to be caused by the teeth of fellow dolphins (Rissos have up to 14 teeth on the lower jaw), but also by their main prey, squid. They are born a dark grey but gradually become paler with age, with this scarring making the older individuals appear almost entirely white, especially on the head. This extensive pattern of scars and scratches means individuals can be identified using photo ID techniques, mostly focussing on the dorsal fins. So far they have not been as well studied as some other species of dolphin, due to their their timid nature and preference for deep oceanic waters. Click here for more information on the species and some great photos on the website of the Whale and Dolphin Conservation Society.


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