Dolphins are very intelligent and social. They send visual signals to each other with their heads, fins, and tails. They use touch.

They also make a lot of noises, such as squeaks and whistles. They have excellent hearing. They also have excellent sound processing in their brains. They can use a process called "echolocation" to hunt fish, tell where the other dolphins are, and avoid objects. Echolocation is also used by bats. It's similar to radar. The animal sends out a sound, then hears it when it bounces back. This gives them a "picture" of their environment. That takes a lot of brain power.

What kinds of things do you think dolphins need to communicate?

Dolphins live in the ocean, which is mostly salt water. Light and, by extension, electromagnetic waves in general do not travel far in the water. Since dolphins have not mastered the extremely low frequency radio communication technology yet, they need to use sound for long range communication.

Human vocal cord is located in our larynx. The phonic lips is the equivalent in dolphin and other teethed whales. It is located in their version of nasal cavity, below the blowhole. The phonic lips can vibrate when air passes through and produce sound. The melon, which is in front of the cavity, shapes the sound beam so it would be useful for echolocation. Dolphins use this system for both echolocation and communication. Except the sperm whale, all teethed whales have two sets of phonic lips so that different sound can be produced.

Marine biologists have recorded whistles, pulsed signals, and other sounds from dolphins. However, due to the challenges of observing dolphin behaviors underwater, what they are communicating remains unclear.

Dolphin communication is very similar to human communication! Like us, dolphins can vocalize (make noises) and use body language to talk to each other. Dolphin vocalization can include whistles, clicks, and sound packets called burst pulses. Each dolphin even has their own unique, signature whistle to identify themselves. However, we don't know what every whistle and click means yet. Some scientists are trying to talk to dolphins using a computer called CHAT (Cetacean Hearing And Telemetry) that can broadcast recorded signature whistles, although that has not had much success yet.

Dolphin body language involves anything from headbutts, slapping the water with their tail or flippers, leaping out of the water, and touches. They can show aggression through headbutts or charging at each other. On the other hand, they can also show affection through gentle bumping and touching.

Dolphins make noises. Some of these are whistle-like sounds, while others resemble clicks. It is probable that dolphins use the whistles for identification, much the way you use your signature to identify yourself. It is also possible that dolphins have other means of talking to each-other that we don't know about yet, too!