06.07.2021 – Breathing freely

Three Bottlenose dolphins (Tursiops truncatus) were our oceanic escort today. After carefully approaching them, they were ready to let us take part in their everyday lives for a while. They moved calmly parallel to the Ribeira Brava. Two dolphins swam side by side in unison: This is a form of non-verbal communication that gives the animals a sense of togetherness. One of the two animals exhaled each time before surfacing. This created a chain of bubbles. Marine mammals have many nerve endings around the blowhole. This allows them to feel exactly when they are above the surface of the sea and can breathe in without water entering the blowhole. The breathing process is quick. When diving, the blowhole is closed by strong muscles so that no water can penetrate the lungs. During exhalation, a so-called spout is often created, which is small and bushy in Bottlenose dolphins, but in baleen whales can protrude four to five meters, sometimes even nine to ten meters (blue whales). Since marine mammals use 90% of the oxygen in the air they breathe, it is possible for them to accumulate enough oxygen in their myoglobin-containing muscles and in their blood system. This allows them long dives and makes it possible that they take far fewer breaths per minute than we humans (with an oxygen consumption of approx. 10%).

A photo was worth including in today’s photo gallery. In this photo, the sea looks “divided in two”. On the left, a cloud-free sky is reflected in the blue sea, on the other hand, one sees the reflection of the cloud cover, which gives the sea a different color.

By Fatima Kutzschbach

Sighting of the day

Ribeira Brava

10.00 Bottlenose dolphins, Loggerhead turtle