29.12.2025 – Sailing voyage

Our Ribeira Brava in the past was a sailing vessel and sailing has been around now for millennia here on earth, but the principle of sailing is not unique to us humans. Animals sail too and today we encountered such a natural sailor, the By-ther-wind sailor (Velella velella). This is a hydrozoan, which are related to jellyfish. The key difference is though, that jellyfish are one organism and hydrozoans are colony of dozens of small polyps. Every polyp has its own role. Some hunt and are situated on the tentacles, other do the reproduction and others build the structure and only together they can survive. This sailor has a small transparent sail which it can use to drift and catch the wind and like that they can travel large distances through the ocean. On the way they passively hunt for prey like copepods and other small organisms. Truly some fascinating critters.

Apart from this sailor we also encountered a dolphin species. It was the Risso’s dolphin (Grampus griseus). This is a rare visitor of this island. They are shy animals, why a sighting is generally difficult. They striking white bodies, at least older and bigger animals and this coloration is not due to a lack of pigments. The white coloration’s comes due to scars which they get by fighting between each other and and with predators and prey. The white coloration’s is like a status symbol, as it could be shown that a whiter body leads to a higher reproductive success.

By Horst Schulte 

Sightings of the day

Ribeira Brava

09:00 Risso’s dolphins

13:00 No sightings

Stenella

09:30 Risso’s dolphin, By-the-wind sailor

13:30 By-the-wind sailor