I don’t deny my own ignorance on this matter; during a family holiday in Orlando in 2009, I left the San Diego SeaWorld park with a sense of marvel at how well the whales appeared to work with their trainers, and was fully convinced that the animals were happy and well. So it was with horror that I learned of some of the organisation's practices, such as separating mothers from their calves, and I'm delighted that pressure from campaigners has finally forced the San Diego park to phase out its public killer whale displays.
But what really struck me while watching Blackfish was the loyalty and methods of communication used within whale communities. I was inspired to find out more.
Why whales sing
The first recordings of humpback whales were made off Hawaii, by the US navy during the cold war in the 1950s. It was not long before researchers were able to associate specific sounds with certain activities – though the exact purpose of whale noises has provoked much speculation.
Not all whales sing; in fact, few species really do and toothed whales communicate with clicks and whistles. Among those that sing are the humpback, blue whale, fin whale and bowhead. It was originally assumed that whale song is used by males to attract a female, and there is some evidence linking singing with the mating season. However, there is little evidence to suggest that females approach singing males, or of a connection between how well one sings and how successful he is with females.
Other theories for the purpose of song during the mating season include synchronisation of female hormones, male bonding and support during this time. An interesting observation made by biologists at the Whale Trust is that signals made by male humpbacks momentarily cease when two males meet, interact for a while and then separate. When each moves off and meets another male, this behaviour is repeated - suggesting that the song is more about networking than mating. In other cases males have been observed singing in tune when together, and even singing the same song when separated by vast distances.
Whales also sing, it is thought, for navigation, alerting others to danger or food sources, and rearing calves. A whale will also sing when bereaved, or isolated from its pod, which can happen when loud sounds from ships interrupt whale song.
The importance of sound
According to the National Geographic, blue whales are solitary creatures: travelling alone, in adult pairs, or as mother and calf. Even then, they can swim several kilometres apart, only congregating to feed.
This is one example of why sound is vital to marine mammals. In an environment where smell is limited because molecules diffuse slowly through liquid, and vision is restricted due to the scattering of light by water, particularly when diving, whales rely on sound. Sound waves travel faster through water than air - perfect for marine communication.
Blue whales have exceptionally deep voices, as low as 14Hz, which is well out of human hearing range. They can also travel for thousands of miles, and are among the loudest animals on earth.
The humpback whale song has a clear structure. It can be broken down into units, which are the shortest sounds that seem continuous to the human ear. These can be wailing, moaning or shrieking sounds. A phrase is made up of six to eight units, and phrases repeated over a period of minutes form a theme. The song is composed of repeated themes and can last between seven and 30 minutes. Songs continue without breaks, often for hours or days.
There are variations in the composition, such as extra units or phrases, but songs are essentially very similar from one version to another, although they evolve over time and with the changing seasons. Whale songs thus have both structure and rhythm. Whale Trust biologists have found that the same or similar songs are repeated across an entire humpback population.
Learning whale songs as a second language
What I found most fascinating of all was the research led by Ellen Garland from the University of Queensland, about humpback whales in the South Pacific. There is strong evidence that elements of songs learned within separate whale populations are passed from one population to another; researchers call it “transmission of cultural trends”. Studies show that types of songs are gradually spread across geographical regions over a period of several years. This exchange of songs might occur on shared migration routes or feeding grounds.
Songs from very isolated whale communities remain dissimilar, but marine biologists have also detected dialects from different regions, where the whales' songs are similar but with slight variation. A pod will have its own dialect, as calves mimic their mothers' songs.
Some people postulate that whale song is not a language at all, and that the animals are not communicating information in any real sense. But the strong sense of community and teamwork among the whales, and the evidence of the link between different sounds and specific behaviours, makes me think otherwise. In fact, I think we can learn something from whales that are so open to communicating in another's language.