May10

Magnificent Qualities of a Common Dolphin

Categories // Hebrides Wildlife Officer

Magnificent Qualities of a Common Dolphin
Photo credit: Andy Gilbert

What is it about common dolphins that makes them so endearing? 

They are the most regularly recorded marine mammal in ORCA’s database. They can be seen all around the world and their global population is likely to be in the millions.  Yet even the most hardened, grizzled old whale watcher will melt before them in just the same way as a fresh faced novice bewitched by dreams of the dolphin’s smile.  Over the years, I’ve had tears and hugs from so many people of all ages when I’ve shown them their first dolphin and invariably it was a common one.  But if ever there was a species more unfortunately named this is it. Delphinus Delphis: the short beaked common dolphin, may be found in relatively large numbers, hence it’s unfortunate title, but it is far from ordinary or “common” in its qualities. In actual fact its qualities are quite magnificent.

This week, on our monthly ORCA Marine Mammal Survey from Castlebay, Barra to Oban on the Scottish mainland, we recorded a wonderful pod of over 100 common dolphins close to the Isle of Coll.  My Wildlife Officer colleagues further south on the Bay of Biscay ferries will scoff at such a paltry number, regularly seeing hundreds if not thousands sometimes as they sail south towards the warmth of Spain but this was a good size group for the Inner Hebrides in early May.  So far this season we have picked up smaller groups of this species.  They live in what is termed a “fission-fusion society” where in periods of low food availability they operate in smaller groups and hunt over a wider area.  When there is more prey available they come (or fuse) together in greater numbers and form large groups and cooperatively hunt big shoals of fish.   

The dolphins that we recorded from the bridge of CalMac’s MV Isle of Lewis exhibited all of the qualities that make them so endearing. Enthusiasm is attractive in any individual and common dolphins certainly display this in bucket loads when they stop what they are doing and diagonally race towards the sound of an approaching ship. In doing so they porpoise out of the water and re-enter with a splash that declares their arrival long before the actual body of the animal becomes visible to the naked eye.  They can reach speeds of over 20km per hour in short bursts and it is thought that they leap out of the water when travelling at speed in order to reduce ergonomic drag by spending time flying through the air rather than battling through the thicker compound of H2O.

As they fly through that air they reveal their least ordinary attribute: their sheer simplistic beauty. With clearly delineated lines their dark triangular cape covers the top of their back and curves down to form the narrow pointed waistline of the often described, hour glass markings. The thoracic patch or coloured side panel at the front of the body varies in intensity and ranges from beige to bright yellow in colouration depending on the individual animal and the light conditions.  It is this and a dark mascara like eye stripe that makes the dolphin so attractive, and so easily identified.

It really can only be the chance to play that attracts them to large ships.  It is noticeable that when they are feeding they ignore us but at other times they come to play, deftly bow riding the ship or acrobatically surfing the wake at the back. That cheekiness and excitement that they exhibit when work is done and playtime has arrived, is something that we all relate strongly to. And perhaps the most endearing quality of all is that at certain times of the year they do this with young calves in tow.  In amongst the racing pods, mothers can be seen with their calves side by side, swimming in total synchronicity. We saw as many as six calves this week, the first that I’ve seen this year, and an indication that spring is now well advanced. 

As soon as they appeared they were gone, left behind in our long wake but also spatially gone as the very next day I transected within a mile of the same area and there wasn’t a peep out of a common dolphin anywhere, such is their mobile nature.  What I do know from my encounters with them is that they will turn up regularly throughout the coming months and that they will always bring, at the very least, a smile to my face and to the passengers out on deck with me.        

Andy

ORCA Wildlife Officer - Hebrides