An adult male orca is an impressive beast and one not to be trifled with. Six tons of flesh, bone and blubber constitute this imposing dolphin. For all of his potential brute force and physical abilities, this male has a surprising secret, he is the ultimate Mummy’s boy.
He will live out his whole life in the family fold with his mother charting his course. Daddy is nowhere to be found. He was a romantic interlude many moons ago that lasted no more than an aquatic tryst. The young male progeny will go from a playful young buck to an impressive bull that will dwarf his mother. Adult females usually weigh between 3-4 tons, Their dorsal fins are less than half the size of the males prodigious 1.8 m (6 foot) fin which is so large that it provides a daunting spectacle on rapid approach.
Orca society is matriarchical and functions in a somewhat similar way to elephant society. The mother is the figurehead or matriarch of the family. She is responsible for keeping the family unit cohesive and for establishing feeding and migratory patterns. Her longevity and knowledge is pivotal in keeping the family together and for finding resources. Surprisingly, mothers tend to long outlive their sons and there is an interesting, albeit unfortunate reason for this.
In British Columbia, Canada there are 4 distinctive orca ecotypes, transient orcas that only eat mammals, resident orcas that only eat fish (one Northern and one Southern population) and offshore orcas that eat mainly sleeper sharks. For transient orcas in particular, there is a tendency to bioaccumulate large quantities of toxins in their body tissues. Being a top predator results in a toxic load accumulating in their bodies from the prey they are consuming over the course of their lives. When a female gets pregnant and gives birth, her first baby gets a particularly heavy hit from the toxins in its mother’s body. This is exacerbated by her milk, more toxins get passed unwittingly to the oblivious baby. This consequently diminishes a female’s toxic load over the course of her life each time she has a baby. Males are unable to offload this toxic burden so become more heavily loaded over time. Males tend to die younger as a result, with an average lifespan of 30 years, whereas wild females average 50 years, with some living into their 80’s and 90’s.
The male orca that has lived alongside his mother and siblings obviously has needs of his own but how are these satisfied when he is kept busy fishing for the family as well as babysitting? Luckily Mum has some other orcas that she knows who have some eligible lasses for her son to go and have some fun with. When the opportunity arises and one family happens to come across another then it is game on! When the male is sexually mature (usually from the age of 15) he will be free and ready to court a lucky lass from an unrelated family. Their encounter will be brief, he will go back to Mum and the rest of his family, as will she. If his conquest becomes pregnant, her family will help her raise her baby. The male that she tangled with will go back to his family and help raise any new babies his mum or sisters will give birth to.
The matriarch will go through menopause in her forties just like we do but will continue to live on and dote on her family and grandchildren. It has been found that even grown males who lose their mothers tend not to fare so well, and many even die after losing her. It is believed a combination of protection, companionship and assistance are important factors in maintaining the well being of the orca unit. And we thought our family bonds were strong?
Suzanne Burns 2014.