26.08.2026 – Sharks are around the corner
September 2, 2026
28.08.2026 – Nature is no museum
September 4, 2026
On our tour today, we were lucky enough to see two very different toothed whales: Bottlenose dolphins (Tursiops truncatus) and Short-finned pilot whales (Globicephala macrorhynchus). This led to an interesting question: If pilot whales dive so much deeper than bottlenose dolphins, how is their body adapted to cope with the enormous pressure?
Short-finned pilot whales around Madeira have been recorded diving to almost 1.000 metres. At that depth, the pressure is around 100 times higher than at the surface.
One of the most important adaptations is found in their lungs. Unlike humans, deep-diving whales are able to let their lungs compress as the pressure increases. Their airways and chest are specially adapted to cope with these changes without being damaged. As the lungs become compressed, gas exchange is reduced, which also limits the amount of nitrogen entering the bloodstream. This helps protect the animals from problems similar to decompression sickness in human divers.
But if their lungs are compressed, how do they get enough oxygen?
The answer is mainly oxygen stored in their blood and muscles. Whales and dolphins have high concentrations of haemoglobin in their blood and myoglobin in their muscles, allowing them to store much more oxygen than land mammals. During a dive, their heart rate also slows down and blood flow is prioritised towards vital organs such as the brain and heart.
Bottlenose dolphins have many of these same adaptations, but their dives are generally less extreme. Pilot whales are especially well adapted to spending time in the deeper parts of the ocean.
by Malina Labowsky
Sightings of the day
Ribeira Brava
09:00 Short-finned pilot whale, Bottlenose dolphin
13:00 Bottlenose dolphin
16:30 No Sightings
Steno
09:30 Short-finned pilot whale, Bottlenose dolphin
13:30 Bottlenose dolphin
16:30 Bottlenose dolphin, Rissos’ dolphin
