…A question that sometimes occurs when I tell people that I study the sounds of the whales. Still, my very close non-scientists friends do think that I try to talk to dolphins. This might not be accurate since my research equipment and purpose of my study do not allow anything like this, but essentially I do try to spy on their “conversations”.
One of the functions of sound in dolphins and whales is communication. Communication is a keyword in bioacoustics and is defined as being “the transmission of a signal from one organism to another such that the sender benefits from the response of the recipient”. There are different purposes that it serves living organisms and different ways to express it.
A primary purpose of communication is to attract and repel. Plants use chemical signals that get transmitted through the air or their roots, people use the smell of pheromones to attract each other, and skunks use the same signal to repel. Dogs and foxes use face and body gestures to express submission and aggression. Elephants use touch interlinking their trunks as a means of close communication. Especially for attracting mates, vision (peacock elaborated feathers) and sound (bird songs) are both very useful.
Though the most common well-known animal communication signal heard by humans is the bird song, there are all sorts of animals that rely on their hearing and vocal ability to succeed and survive. Whales, the modern giants, appear to be experts in the art of sound communication with different species each having their own sounds. They use these sounds to navigate, locate and capture prey, communicate about the environment and the availability of food or predators, and to attract mates or repel competitors.
Such acoustic signals may be (a) instinctive that is genetically programmed or (b) learned from others through social learning.
Social learning is the information moving through communication from one organism to another. This information then passing on is what we call culture. Without this transfer there would be no life, no evolution, no biology. Culture is why we have the Parthenon, the South Park, boy bands and the MIT. What you read, like this blog, that you may pass it on is culture.
Cultural transmission, the social learning from conspecifics is believed to occur in a number of groups of animals, including primates, cetaceans and birds, elephants and bats. Cultural traits can be passed through different paths.
Cultural transmission can be done vertically: from parents to offspring, obliquely: from the previous generation via non related individuals to younger individuals, or horizontally: between unrelated individuals from similar age classes or within generations.
Of the several types of social learning which have been recognized, imitation is particularly significant for the propagation of culture. Humans can imitate new sounds and learn how to use them correctly in social situations. This is called vocal learning which is considered to be one of the foundations of language.
My favorite example of imitation in the animal kingdom is the lyrebird of S. Australia, which has an unbelievable capacity for mimicry. During the breeding season in South Australia, the male lyrebirds spend six hours a day calling, doing their best to attract the ladies. They have the most complex syrinx (vocal organ in birds), and they make a remarkable use of it!
I know I am repeating myself since I have posted a video of the lyrebird before but this time the famous mime has enriched its repertoire with more sounds that will make you wonder how and why… Check out the lyrebird’s latest hits here.
Next I would like you to meet Luna, another excellent mime; Luna is a male orphan killer whale. Luna has been all alone since the age of two, living off the coast of Vancouver Island, Canada. There, in 2001, Luna became popular for getting in close proximity to people, interacting with local boaters and perfectly mimicking boat noises. A tragic result of this interaction was the tragic death of Luna in 2006 due to a tugboat collision!
Culture, through social learning, has been studied and papers have been published mainly in only four species of cetaceans: (1) the humpback whale, (2) the sperm whale, (3) the killer whale, and (4) the bottlenose dolphin.
Humpback: the Diva
Humpbacks are the most popular singers of probably all the non-human mammals. They have even released CDs with their songs ! When we think of whale songs the humpback is what we have in mind. They represent the best understood horizontal culture of cetaceans.
The males produce series of vocalizations that form songs used in sexual selection (through mate attraction and/or male social sorting). Their songs are very complex and can be heard mainly in breeding grounds and whales can hear them up to 10 km (about 6 miles) away. Whales sing the same song for hours and hours. Populations within an ocean basin have similar songs with this similarity dependent on geographical distance between populations.
Humpbacks can change their song after hearing other songs. A terrific example takes place in the southern ocean where the songs are horizontally transmitted from eastern Australia in the west across the region to French Polynesia in the east. The songs have been documented radiating repeatedly across the region from west to east, usually over a period of two years. The result: soon the song that was recorded on the east region is now fully replaced by the west region hit. This seems to me to be really similar to our music culture transmission.
Killer whales: The Intellectuals
The Sea Pandas (as some marketing teams have proposed renaming killer whales to help promote their conservation) are highly social.
The populations off the west coast of Canada have been studied for decades and are divided in different ‘‘types’’: the residents, transients and offshores. These 3 different types have diverse feeding preferences and subsequent vocalizations. The residents feed on fish and are highly vocal, the transients feed on marine mammals and are much quieter to not reveal their presence to their prey that has good hearing abilities. The offshores are also highly vocal and feed on sharks and rays.
Killer whales that are separated by great geographical distances have completely different dialects. An analysis of Icelandic and Norwegian killer whale pods revealed that the Icelandic population made 24 different calls and the Norwegian whales made 23 different calls, but the two populations did not share any of the same calls.
Besides dialects, killer whales have been shown to learn vocalizations from other species. Yes, they speak foreign languages! At a water facility, where they socialized with bottlenose dolphins, they changed the types of sounds they made to resemble those of their neighbors.
If I was not so enthusiastic about the sperm whales, killer whales would definitely receive most of my scientific admiration. They have evolved outstanding sophisticated hunting techniques and their vocal behavior is impressive, being specific to certain groups and passed across generations. Killer whales are great examples of cultural organisms.
Keeping these animals in captivity sounds like even less of a good idea now, right?
Bottlenose dolphins: the Eponymous
Bottlenose dolphins are well known for their signature whistles. They have stereotypical signatures attributed to each individual that work as their name. This helps to maintain contact between mom and calf or between individuals in a group. Each bottlenose dolphin has its own unique whistle and it uses it to broadcast their location and identity to others.
Most of the characteristic whistles are usually fixed for all the lifetime of the dolphin. However in some cases, when a male dolphin leaves mom and joins with other males to form an alliance (which might last for decade), their distinctive whistles converge and become very similar. So the longer they stay together the more similar their whistles become. Based on the same reasoning, I can’t understand why my English accent is still the same after three years living in USA!
Sperm whales: the Bignose
Sperm whales are among the loudest animals on Earth, and my favorite (not sure if I have already mentioned my preference). They owe this to their huge nose which functions as a massive click producer. They also have the biggest brain. They produce a variety of loud and distinctive types of clicks for different functions. One of these types of vocalizations is called coda. It is stereotypical patterns of clicks resembling Morse code, and frequently serves social purposes. Codas are usually heard when the group of animals rest or socialize at the surface of the ocean. Similar codas used by one group may help maintain group cohesion after its members are done feeding.
It is thought that each sperm whale has its own individually distinctive coda pattern and it has been reported that groups within one geographic area tend to have more similar codas than groups from further away. The “five regular” call is one of the few codas that all sperm whale groups around the globe use in their regional dialects; while the “plus one” type seems to be specific to Mediterranean inhabitants. These vocal behaviors are transmitted vertically, and loosing members of the population may seriously impact the transmission of this cultural trait that carries important information content vital for the survival of the population.
We don’t need to watch Interstellar to search for life in different solar systems and unknown worlds. Like Anne Stevenson said: “the sea is as near as we come to another world”. The ocean is vast largely undiscovered. We can consider the open sea an intriguing new wet universe. In interstellar, communication or miscommunication played an important role and turned out to be vital for rescuing the world. Father and daughter that could not directly speak to each other used binary code to transmit their messages through different dimensions. The cetaceans also transmit their messages through codes that we try to identify and understand. It is vital for their world to be able to use these sounds to communicate. You can correctly guess that we are using their home for our anthropocentric purposes and we are being very noisy neighbors, polluting their ocean and impacting their survival. This can be changed… If you are looking for New Years resolutions…
Like in the movie, it’s not Them that will help us save the world. No external factors are required, all the power is in us!
Happy, quiet and peaceful holidays to y’all!!
This post was inspired by the presentation that me and Selene gave on Saturday 12/13/2014 for the Oregon Chapter of the American Cetacean Society entitled: “Do you speak whale?”.