Sightings of Risso’s dolphin are hardly common in the Gulf of Corinth – researchers at the Pelagos Cetacean Research Institute of Greece have documented only two individuals in the entire area. The Tethys team themselves have spotted this species only once prior to today’s sighting, identified subsequently as the same individual sighted yesterday. Thus it is perhaps understandable that professionality climbed out of the boat and swam off for the initial few minutes of the sighting, as Silvia and I proceeded to jump about the boat, exclaiming in barely-restrained elation.
Observing this magnificent creature, even for a short period of time, reveals the true extent of their behavioural complexity. Throughout the duration of the sighting, this large dolphin was exhibiting what could only be described as ‘play’ behaviour, nosing up underneath a Cotylorhiza jellyfish, flipping it back and forth between caudal and dorsal fin. The true purpose behind this activity is unknown - due to our regrettable inability to communicate with the individual – however, it may be theorised that this behaviour arises as a result of social exclusion from its own kind, or simply a reflection of the complex ‘personality’ traits exhibited by higher order mammals in this way. However anthropomorphic it may seem, the Risso’s was visibly enjoying itself, albeit to the extent of the unfortunate jellyfish.
The most striking point of interest taken from this sighting was the presence of the single Risso’s dolphin amongst a mixed group of striped and common dolphins. The astoundingly high level of interaction between the Risso’s and the other dolphin species indicated how deeply integrated the individual has become. Gliding side by side, the striped, common and Risso’s dolphins give a lesson in the achievement of peaceful co-habitation.
Border disputes and territory skirmishes mean nothing to these animals, as newborn striped dolphins hurtle themselves across the water surface in and around the larger un-related animal. The trust exhibited by the striped and common dolphins towards the Risso’s – in tight formation for the majority of the sighting - leaves the observer incredulous. The individual exhibited apparent protective behaviour over the smaller dolphins - encircling the boat, remaining in a constant shielding position between our vessel and the focal group. The animal maintained an aura of both dominance and care, ensuring the safety and security of those individuals that have welcomed it into their social network in the absence of its own kind.
What struck my pensive mind during the sighting was the juxtaposition of this inter-specific trust and integration, with the equivalent human context above the sea. We humans instigate whole dossiers of law and legislation before any form if immigration program can be established in a country. In our world, sociality is often divided by race, religion, borders and resources. Life for us is to be fought, not shared. This marine mammal microcosmos, however, was apparently untouched by such forms of division. Whilst our people are torn apart by petty disputes, these animals have found a way to co-exist and benefit from that which is necessary to all living creatures – the comfort of others.
Philippa Dell (Research assistant, Coastal Dolphins Greece)
Frantzis A., Herzing D. 2002. Mixed-species associations of striped dolphins (Stenella coeruleoalba), short beaked common dolphins (Delphinus delphis) and Risso’s dolphins (Grampus griseus) in the Gulf of Corinth (Greece, Mediterranean Sea). Aquatic Mammals 28(2):188-197.