04.02.2019 – Recharging at the surface
In spite of their incredible agility, their remarkable intelligence and skillful coordination, hunting still demands high energy expenditure in cetaceans. So, like us, they also need to take a short break once in a while to tend to social matters or simply recharge at the oceans surface.
Short-finned pilot whales (Globicephala macrorhynchus), for instance, engage in metabolically-expensie deep sprint dives to hunt squid in the dark ocean, during which these „cheetahs of the ocean“ are thought to reach velocities of up to 9m/s. These swift pursuits are largely nocturnal and occur after dusk when squid and other deep-scattering-layer (DSL) organisms take on their daily vertical migration to shallower areas of the water column. This strategic timing of their hunts allows pilot whales to conserve energy and they then use the daytime hours to rest at the surface and engage in social activities. This resting behaviour is referred to as „logging“ and was also witnessed today during our tour on board the Stenella.
The Bottlenose dolphins (Tursiops truncatus) we encountered off the coast of Jardim do Mar were still preoccupied with hunting as we arrived at the sighting. While the majority of the group were leaping and speeding at the surface, others took a brief time-out from their pursuit to enjoy a bowride on the waves of our zodiac.
Before our sighting with the Bottlenose dolphins we came across a juvenile Loggerhead turtle (Caretta caretta) having a short breather (quite literally) between foraging dives. Many of the young reptiles spend a part of their juvenile oceanic life phase feeding in the offshore waters of oceanic islands such as Madeira. In between their dives, turtles rest at the surface in a behaviour that is commonly referred to as „basking“. Here they catch their breath, relax and use the suns rays to regulate their body temperature and digestion.
Of course these resting situations are a granted sighting for our team and guests but we do our best to respect the animals quiet time and approach the area as carefully as we can. After all, nobody enjoys being disturbed while they’re resting and even cetaceans need to unwind.
By Paula Thake
Sightings of the day
10:00 Bottlenose dolphins, Short-finned pilot whales, Loggerhead turtle