The north wind has brought chilly temperatures to the archipelago, with some weather stations even forecasting snow on Madeira’s peaks. Today was a particularly cold day but the weather was ideal for whale-watching! Besides, how welcoming is the thought of having your heart warmed by dolphins on a chilly day?
Ironically, the first dolphins we met on this chilly day happened to be our summer dolphins, the Atlantic spotted dolphins (Stenella frontalis). These warm-water loving dolphins are by far the most abundantly encountered cetacean in the summer months but also visit us in winter, mainly to use the waters as a temporary safe haven for their little ones. It’d hard not to feel happy when meeting spotted dolphins, their curiosity and cheeky behaviour could melt even the coldest of hearts!
Dolphins are warm-blooded just like us, meaning they are able to keep their body temperature constant (at around 37ºC) and do not rely on environmental factors to do so. Life in the ocean is generally colder, especially in deeper layers, but through their body’s own thermoregulation they will somehow keep warm. Generally speaking, a dolphin’s metabolism is higher than that of land mammals of similar size so it generates a great deal of heat which isn’t lost as quickly through respiration since they breathe less frequently. The body is also insulated through a layer of blubber which protects against temperature changes and body heat is conserved through transfer from one blood vessel to another. For example, during dives blood circulation is concentrated into the dolphins core organs and tissues and reduced in the outer portions of the body. Dolphins expel excess heat through their dorsal fin and flukes.
We met spotted dolphins in the morning aboard our traditional boat and again in the afternoon on board our speedboat. Our Stenella even managed another sighting with Bottlenose Dolphins (Tursiops truncatus) aside from the sighting with her namesake dolphins. These incredibly adaptive dolphins are widely distributed across the planet, adapting to all kinds of weather, with the small groups in Madeira still enjoying the 20ºC water. What a lovely day!
By Paula Thake
Sightings of the day
10:30 Atlantic spotted dolphins
14:00 Atlantic spotted dolphins, Bottlenose Dolphins