Five Amazing Dolphin Behaviors, Explained
From calling each other by name to using tools, these social creatures are a lot like us
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Despite our completely different environments, people love connecting with dolphins: swimming with them, playing with them and learning about them. We might feel so connected to them because we have a lot in common with these underwater animals. They have large brains relative to their bodies, like us, and they form flexible social groups as well as close friendships that can last decades. Dolphins also seem to show cooperative behaviors and to work well as a team.
To understand why dolphins act as they do, we scoured the web and called three experts. Read on to dive into the reasons behind their behaviors.
Dolphins likely call each other by name
The marine mammals have “signature whistles.” Each individual creates a unique sound to identify itself. And other dolphins recognize the call as belonging to that individual. Dolphins typically develop their signature whistles by about six months of age, and the whistles are very distinct from one another. Laela Sayigh, dolphin communication specialist at Woods Hole Oceanographic Institution, and her research team found when playing recordings of these whistles, wild bottlenose dolphins were more likely to respond to whistles from individuals they were close to. Dolphins can also mimic each other’s whistles, possibly to address or call each other.
Closely bonded adult male dolphin pairs can have signature whistles that become more and more similar over time. “We’ve seen lots of examples of very tight male alliances that have almost exactly the same whistle,” says Sayigh. “It could almost be almost like a badge [saying], ‘We’re together, we’re this pair.’”
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Since dolphins live in large interconnected groups, interacting repeatedly with different individuals over many years, identifying individuals is important to maintaining long-term associations. Research has even shown dolphins can remember the signature whistle of a former friend decades after last seeing or hearing it.
They have different “personalities”
After decades working with dolphins, Bruno Díaz López, dolphin expert at the Bottlenose Dolphin Research Institute in Spain, says dolphins are individuals. “When you study these animals, when you live with them, see how they grow, and see how they act … you know that they have a personality,” says Díaz López.
Díaz López’s research team measured these differences by looking at how wild bottlenose dolphins responded to new items and situations, for example how willing a dolphin was to approach and investigate a human diver, or a speaker playing a sound. The researchers then classified individual dolphins on a continuum of boldness to shyness: Shy individuals were less likely to approach. Bolder individuals turned out to have a more central role in the social network, with stronger relationships than more shy dolphins.
Dolphins’ social personality traits also stay the same over time, according to another study in wild bottlenose dolphins. Over 32 years, traits parallel to introversion and extraversion in humans—measured by time spent alone, time spent in large groups and number of relationships—remained stable in individual dolphins from infancy through late adulthood. Like signature whistles, this personality stability could be useful in complex social societies: understanding how bold or shy members of the group can help dolphins better form long relationships.
Dolphins communicate through touch
Dolphins don’t produce sounds through their mouths, but through their blowholes, by moving air through interconnected air sacs. And they don’t use their ears to hear underwater; they “hear” by sensing vibrations in the jawbone, which connects to their brain.
These whistles and squeaks are important, but they’re not the whole story of how dolphins communicate. Díaz López’s research team found very close friends didn’t vocalize as much with each other. “Maybe because they know each other so well, they don’t need to communicate as much,” says Díaz López.
Or, dolphins may not use sound because they also rely on body language and touch to communicate, explains Heidi Lyn, animal communication specialist at the University of South Alabama. “You see a lot of social behavior where they are touching pectoral fins, so their front flippers, they’ll rub them alongside each other, or they’ll touch fins as they’re swimming.”
“One of the coolest things that dolphins do to form these bonds is synchronous displays and behaviors,” says Lyn. This coordination can happen without much vocalization, according to Lyn: One dolphin can very closely watch and mirror the body motions of another. “That is something dolphins are really good at, reading each other’s body behaviors and syncing up, forming bonds in that way,” says Lyn.
They use tools
Some dolphins are more curious than others, exploring new objects or innovate new behaviors more, according to Heather Hill, dolphin behavior expert at St. Mary’s University in Texas. “There are individuals who seem to ‘get it,’” says Hill, which are the dolphins that tend to come up with new solutions to problems in the wild.
Curiosity and creativity help dolphins discover new solutions to problems, like using tools. Some dolphins in Australia use a technique called “sponging”: They wear a sea sponge on their beak and use the sponge to uncover food on the seafloor. The same group of dolphins invented “shelling,” where a dolphin traps underwater prey in a sea snail shell, pokes its beak into the opening of the shell and lifts the shell above the surface of the water to shake contents into its mouth.
Dolphins team up with humans
Dolphins around the world have learned to take advantage of people fishing. Along the coasts of Spain and Italy, dolphins swim around fish farms to herd the fish that gather around floating rafts of mussels or shellfish. They also work together to steal fish from nets. Dolphins seem to prefer associating with other dolphins that use similar feeding strategies, and they share these techniques with their friends.
But this is not just a one-sided relationship—human fishers cooperate with dolphins, too. According to Díaz López, accounts of human-dolphin fishing collaboration go back to ancient Greece and Rome. In Brazil today, fishers looking for migrating mullet fish watch where bottlenose dolphins dive to indicate where they should cast nets. This fishing partnership has been passed down through generations for over 150 years, with dolphins benefiting as well. After the fishers cast nets, the marine mammals eat disoriented fish that aren’t caught. These Brazilian dolphins show better survival rates when they work alongside fishers.
Unfortunately, large-scale and illegal fishing are making mullet scarcer, threatening Brazil’s dolphin-human fishing partnerships—one of the last remaining mutually beneficial ecological interactions between humans and wild animals.
As the situation evolves, the marine mammals will need to adapt. “Dolphin behavior changes—it’s plastic and it changes with the environment and the opportunities they have,” says Díaz López. “But our interpretation of their behavior, how humans view their behavior, has changed more.”