09.01.2020 – Light sleeper

The ocean welcomed us with rainbows in the sky as we sped out aboard our zodiac this morning. Our sightings included bow-riding Striped dolphins (Stenella coeruleoalba), a small shy Loggerhead turtle (Caretta caretta), a By-the-wind-sailor (Velella velella) and several Yellow-legged gulls (Larus michahellis) including one young individual that was nibbling at some leftover squid at the surface. Our last sighting was the longest and was spent with a calm group of Short-finned pilot whales (Globicephala macrorhynchus) that were gently travelling east through the placid waters before being joined by a handful of Bottlenose dolphins (Tursiops truncatus). Whilst the Bottlenose are notorious for their active and dynamic nature, they adapt to the lethargic nature of the pilot whales allowing the large cetaceans to invest more time into an essential activity at the surface: rest. 

Pilot whales engage in metabolically expensive sprint dives into the depths to hunt squid and return to the surface for a well-deserved breather. Resting behaviour of these incredible creatures at the surface is referred to as “logging” by whale-watchers whereby they simply drift with their enormous and buoyant bodies at the surface. These minutes of rest are essential for the whales to recuperate after their strenuous foraging dives, so when we approached the logging bull during todays tour,  we had to make sure to do so carefully and quietly. We obviously weren’t stealthy enough; the large male was evidently a light sleeper and eventually came to and slowly swam off, seemingly annoyed at our intrusion. Well, no one likes to be disturbed resting so we made sure to keep a distance as the rest of the pod began logging before they swam off in unison. 

Recently, an experiment proved that dolphins actually enter the REM (rapid eye movement) phase while they sleep, which is the part of human sleep where we dream. One can’t help but contemplate what these enormous cetaceans dream of and the thought flickered through my head as the whales continued their journey into the vast blue Atlantic ocean.

By Paula Thake

Sightings of the day

Stenella

10:00 Bottlenose dolphins, Short-finned pilot whales, Striped dolphins,  Loggerhead turtles