16.07.2019 – Mama?

Having my mother on board as a special guest on todays wonderful Stenella tour delivered food for thought regarding the upbringing of little cetacean calves and inspired me to share this knowledge with our lovely guests. Our sightings consisted of a pallet of toothed whales today, a family of marine mammals that exist in a variety of social units…and social life in the unforgiving Atlantic Ocean requires some good training!

Of course this training is entirely dependent on the kind of social life you are exposed to and is a question of nature & nurture with dolphins as it also is with human beings. The larger toothed whales such as the magnificent Sperm whales (Physeter macrocephalus) or the gentle Short-finned pilot whales (Globicephala macrorhnychus) exist in matriarchal societies that are dominated by cultures passed down over generations. These female dominated groups are fixed units that unanimously participate in the raising of the young so, essentially, the young calves learn all they need to know from all the females in their herd not just their mothers. In fact, pilot whales are able to suckle young calves that aren’t their own offspring and could do this up to 15 years after reaching an infertile age. This could also mean that the little tiny calf we saw today, was not necessarily swimming near its mother; the female may have also been its sister, aunty, grandmother or a family friend.

With oceanic dolphins, like the Atlantic spotted dolphins (Stenella frontalis), the Short-beaked common dolphins (Delphinus delphis) and the Bottlenose dolphins (Tursiops truncatus) things are a little different and, again, this is due to the different social nature of these communities. Dolphins form fluid groups known as “fission-fusion” societies, ever-changing units that associate and dissociate within random spans of time. At the beginning of their lives, dolphins may travel in nursery groups and are protected by all females in the group but they are raised and taught all they need to know to survive by their mothers. When another sibling is born the young must leave their mothers side and begin to establish friendships and henceforth begin making choices that determine what they will learn in the course of their lives.

According to some studies, a female dolphin may eventually return to her mothers side when she becomes pregnant to raise the calf under her guidance. It wouldn’t surprise me considering that these are intelligent, emotional beings that nurture important relationships. I couldn’t help but remember a little quote I had once given my own mother some time ago “When all else fails, fly home to mum”. I suppose in the case of dolphins, it’s swim home to mum.

By Paula Thake

Sightings of the day 

Ribeira Brava

17:00 Atlantic spotted dolphins

Stenella

09:00 Bottlenose dolphins, Short-beaked common dolphins, Short-finned pilot whales, Sperm whales 

15:30 Atlantic spotted dolphins