Sperm whales’ clicks suggest the animals have culture
Sperm whales love to chitchat. They talk to each other in clicks. Now, scientists say, those clicks hold hints that the whales have culture.
Culture is a way of life passed on from generation to generation through learning. “There’s a lot of debate if culture is exclusive to humans or if you can find it in animals, too,” says Maurício Cantor. He is a biologist at Canada’s Dalhousie University in Halifax, Nova Scotia. Earlier research had suggested that dolphins, primates, birds and a few other wild animals have culture. Sperm whales should be added to that list, Cantor and his colleagues now argue in the September 8 Nature Communications.
Sperm whales can make some of the deepest dives of all the animals in the sea. They can plunge up to 2,250 meters (7,380 feet) below the ocean’s surface. And they can stay underwater for nearly 90 minutes. When diving, the whales send out loud clicks and listen for the echoes that bounce back after the clicks hit something close by. This is called echolocation. It’s the animal equivalent of sonar, and the whales use it to hunt — mainly for large squid. But when the whales are not hunting, they use those clicks to chat with each other.
Females and their calves do most of the talking. Tens of thousands of them hang out in the warm waters of the South Pacific Ocean. They usually swim in small units of 12 or so moms, grandmas, aunts and friends. These gals all work together to raise their pod’s babies.
These units are part of larger groups of 30 to 300 whales, which belong to even larger communities, called clans. Individuals in each clan talk to each other using distinct patterns of clicks. These varying patterns are similar to dialects in human speech. A dialect is a regional pattern in speech. People in Boston, Mass., and Dallas, Tex., both speak English, for example. Yet they may use words differently or give them a different pronunciation. Those differences reflect their regional dialects.
Cantor and his colleagues wanted to know how the whales got their distinct dialects. The researchers followed groups of whales around the Galápagos Islands, off South America. Along the way, they recorded the whales’ identities and behaviors. The scientists logged the whales' sounds and tracked with which other groups these sperm whales interacted.
Back in their lab, the scientists loaded all of these data into a computer. Then they programmed it to test different ways the whale dialects could have developed over thousands of generations. Perhaps the dialects developed by chance. Or there might have been some innate bits of sound passed from mom to baby through DNA. The computer program ruled out both of those scenarios. Instead, the analysis showed that the whales had to have learned their distinct dialects from the other whales around them.
Scientists refer to this as social learning.
“Social learning is the foundation of culture,” Cantor says. Because sperm whales learn their dialects from their extended family, there are cultural differences between clans. The clans actually exist because of those cultural differences, he says.
Luke Rendell is a biologist at the University of St. Andrews in Scotland. He was not involved in the study. He points out that the new finding is based on a computer model of how the sperm whale dialects came to be. A model, though, can only simulate the real world. It is not a direct observation of what actually occurred. “Like all models, it is wrong, but it is also useful,” Rendell says.
The model suggests whales have a bias for the sounds of their own clan members, which shapes their society, Rendell notes. This kind of conformity, or sticking with individuals who behave the same, is thought to underpin a lot of human culture. In non-humans, however, it is considered rare. Finding hints that it exists in sperm-whale clans “really starts to lift the lid on cultural processes in non-human societies,” he says.
Cantor notes that the scientists are not suggesting that the whales’ sounds or culture are as complex or diverse as human cultures are. But, he says, “Whale culture, like human culture, seems to be very important for the whales’ social structure.”
bias The tendency to hold a particular perspective or preference that favors some thing, some group or some choice. Scientists often "blind" subjects to the details of a test so that their biases will not affect the result.
biology The study of living things. The scientists who study them are known as biologists.
clan A large family or group of families that have much in common, both genetically and culturally.
computer model A program that runs on a computer that creates a model, or simulation, of a real-world feature, phenomenon or event.
culture (in social science) The sum total of typical behaviors and social practices of a related group of people (such as a tribe or nation). Their culture includes their beliefs, values, and the symbols that they accept and or use. It’s passed on from generation to generation through learning. Once thought to be exclusive to humans, scientists have recognized signs of culture in several other animal species, such as dolphins and primates.
dialect A form of language or pattern of communication that is distinct to a specific place or a social group.
DNA (short for deoxyribonucleic acid) A long, double-stranded and spiral-shaped molecule inside most living cells that carries genetic instructions. In all living things, from plants and animals to microbes, these instructions tell cells which molecules to make.
dolphins A highly intelligent group of marine mammals that belong to the toothed-whale family. Members of this group include orcas (killer whales), pilot whales and bottlenose dolphins.
echolocation (in animals) A behavior in which animals emit calls and then listen to the echoes that bounce back off of solid things in the environment. This behavior can be used to navigate and to find food or mates. It is the biological analog of the sonar used by submarines.
generation A group of individuals born about the same time or that are regarded as a single group. Your parents belong to one generation of your family, for example, and your grandparents to another. Similarly, you and everyone within a few years of your age across the planet -are referred to as belonging to a particular generation of humans.
innate Something such as a behavior, attitude or response that is natural, or inborn, and doesn’t have to be learned.
model A simulation of a real-world event (usually using a computer) that has been developed to predict one or more likely outcomes.
pod (in zoology) The name given to a group of toothed whales that travel together, most of them throughout their life, as a group.
primate The order of mammals that includes humans, apes, monkeys and related animals (such as tarsiers, the Daubentonia and other lemurs).
programming (in computing) To use a computer language to write or revise a set of instructions that makes a computer do something. The set of instructions that does this is known as a computer program.
scenario A possible (or likely) sequence of events and how they might play out.
simulate (in computing) To try and imitate the conditions, functions or appearance of something. Computer programs that do this are referred to as simulations.
social learning A type of learning in which individuals observe the behavior of others and modify their own behavior based on what they see.
social network Communities of people (or animals) that are interrelated owing to the way they relate to each other.
sonar A system for the detection of objects and for measuring the depth of water. It works by emitting sound pulses and measuring how long it takes the echoes to return.
sperm whale A species of enormous whale with small eyes and a small jaw in a squarish head that takes up 40 percent of its body. Their bodies can span 13 to 18 meters (43 to 60 feet), with adult males being at the bigger end of that range. These are the deepest diving of marine mammals, reaching depths of 1,000 meters (3,280 feet) or more. They can stay below the water for up to an hour at a time in search of food, mostly giant squids.
zoology The study of animals and their habitats. Scientists who undertake this work are known as zoologists.