31.10.2024 – Mama’s boys and girls

Published by Sarah Kather on November 5, 2024

High winds blowing from the Northwest builded up during the day. They turned our afternoon tours into a combined whale-watching and rollercoaster ride and were the reason we decided to cancel the last trip of the day. Despite the winds, our spotter demonstrated his skills and found two species of cetaceans between all the white caps – Bottlenose dolphins (Tursiops truncatus) and Sperm whales (Physeter macrocephalus). Both groups had calves amongst them. Did you know that the energy that a whale or dolphin invests into childcare is very different from species to species? In Bottlenose dolphins for example, the calf stays by its mother for about the first few years of their lives, getting nursed for at least a year but will eventually start feeding fish already after a few months after being born. At a young age of only 3 years, the calf will often separate from its mother and from that moment on live in a fluid “fission and fusion” society and continuously meet up with different Bottlenose dolphins. A Sperm whale instead will stay much longer by its mothers side – in case of being born as a female, they may never leave their mothers side and stay in so-called social units, being family groups of adult females for their whole lives. One of the reasons for such a big difference in child care is their feeding habits. In general, the more complicated the feeding techniques, the longer the individual whales or dolphins stay together to teach and learn from each other. But even diving depths makes a difference: While Bottlenose dolphins tend to feed closeby the surface, Sperm whales dive regularly to depths of 1000 m – the young will stay closer to the surface and need someone to take care of them. In a Sperm whale family unit, there is always an auntie closeby taking care of the young. It goes as far as the females will nurse each other’s calves. And for how long? This seems to be very variable – a minimum of 2 years seems fair, but there has been an extreme case documented of a male sperm whale teenager containing milk in its stomach at an unbelievable age of 13 years!

by Sarah Kather

Sightings of the day

Ribeira Brava

09:30 Bottlenose dolphins, Sperm whales