01.10.2019 – Cruise control

When identifying cetacean in the wild from far away, size is usually a good place to start. Today was a clear example of that, since the two dolphin species we encountered today differ quite a lot. There’s one small issue with this method, the younger animals, smaller and often more energetic and therefore spotted first. When we get closer, things get easier and when we got close this morning, we had a great observation of Bottlenose dolphins (Tursiops truncatus) Travelling with their young, Bottlenose calves are incredibly cute, sometimes they play and swim around, but more often we see the them close and safe by mommy’s side. Matching the swimming patterns. This has many advantages, but mainly, it is about energy consumption. Swimming around all day, keeping up with the big dolphins can be tiresome for the young calf, of course the group will not leave their young behind, but there’s a nifty little trick that allows the calf to keep up. A young dolphin will swim right under the mother, and as she swims, she creates a slipstream, a hydrodynamic feature that pulls water behind the dolphin. And in that spot the calf can glide along without really swimming much. It’s like cruise control for Cetaceans, as it is used by many species. Without a care in the world the little dolphin glides, goes up to breather sometimes and returns to his spot to surf smoothly.

Another dolphin that we often see making use of hydrodynamic tricks is the Atlantic spotted dolphin (Stenella frontalis). Later today we found a group, far west, in an area we usually don’t visit because it is known for the frequent strong winds that pass the island there. Luckily, today the spot was calm. The hydrodynamic trick I was referring to is bow riding, instead of being pulled by a larger dolphin, these animals let themselves be pushed by a large boat. With the same effect, they can surf a little and have a little fun, before swimming of to continue about their business, which usually means finding fish.

We had to search far and wide today, but our resolve was rewarded, with sightings of these two incredible dolphin species.

By Scott Dorssers

Sightings of the day

Ribeira brava

10:00 Bottlenose dolphins

Stenella

09:00 Bottlenose dolphins

15:00 Atlantic spotted dolphins