09.11.2021 – A deeper mystery

The ocean is full of wonderful mysteries! Despite our incredible technological progress over the past decades we often find that one revelation simply leads to a dozen more questions. It’s humbling and marvellous!

Our Ribeira Brava had to search far and wide for cetaceans today and was able to track down two very well studied species this morning; the Short-finned pilot whales (Globicephala macrorhynchus) moving alongside some Bottlenose dolphins (Tursiops truncatus). Despite the fact that Bottlenose dolphins are probably the best researched cetacean and that we know a fair amount about the social lives of both species, the reasons behind such interspecific interactions still remain a mystery and rest on different theories. Perhaps the opportunistic bottlenose dolphins hope to gain hunting advantages from the pilot whales? Perhaps they are aware of the gentle nature of these large dolphins and seek protection? Or maybe they just enjoy each others company? We simply don’t know.

In the afternoon a deep diving cetacean was foraging around 4 nautical miles offshore and our team made it their mission to find this lonely Cuvier’s beaked whale (Ziphius cavirostris). We generally know very little about beaked whales and the Cuvier is no exception. Beaked whales socialise, communicate and hunt in the depths, spending very little time at the surface. This massively constrains research on their social lives and their behaviour. One thing we do know about the Cuvier is that it is a phenomenal diver. With recorded dives of up to 3000m and with lengths of over 3 hours, the Cuvier is currently the world’s deepest and longest diving mammal. Naturally, their preference of deeper waters keeps most encounters with the species very brief but what an honour it was to be in the presence of such a mysterious record-breaker.

By Paula Thake

Sightings of the day

Ribeira Brava

10:00 Bottlenose dolphins, Short-finned pilot whales

14:30 Cuvier’s beaked whale