01.09.2019 – Shared existence
September 11, 2019
03.09.2019 – A poem about the ocean
September 14, 2019
Every animal has to eat, this goes for us, but also for the dolphins and whales we saw today. The ocean’s plentiful bounty provides ample opportunity for tasty food, as you may have noticed when enjoying one of the many great seafood restaurants on madeira. As the variety of different species evolved over many millions of years, they developed different methods for hunting different prey, establishing their position in a niche where they are the best able to fill their belly’s. This is one of the reasons we have such vastly different animals within the Cetacean order. Some, like the Atlantic spotted dolphin (Stenella frontalis) we saw today, hunt in groups, chasing and herding entire schools of fish to the surface where they can all share in the feast together.
Others like the sperm whale (Physeter macrocephalus) Dive down deep for long periods of time to hunt for squid, going up to 2000 meters deep for 2 hours if needed to find their favourite prey the giant squid. In contrast, the Pilot whale (Globicephala macrorhynchus) dives down in a much different fashion. A straight down high-speed dive of approximately 20 minutes, going around 30 km/h they expend large amounts of energy to race down, hovering at a depth of 500 meters, searching and homing in using their echolocation, and racing off again to catch their prey. It is suggested that their long stays at the surface are not because of a calm gentile nature, but because they are catching their breath from the intense hunting/dives.
The Bottlenose dolphins (Tursiops truncatus) we saw today are quite different at the surface, more likely to approach, and sometimes inquisitive as they bow-ride along our boat. Yet they also have a fondness for the Pilot whales, since we often find them close to each other.
By Scott Dorssers
Sightings of the day
Ribeira Brava
09:00 Sperm whale, Atlantic spotted dolphin
13:30 Pilot whales, Bottlenose dolphin
Stenella
09:00 Atlantic spotted dolphin,
15:30 Atlantic spotted dolphin, Pilot whales, Bottlenose dolphin
