Three basic types of sounds are produced by bottlenose dolphins. They have somewhat overlapping functions.
In general, clicks help dolphins navigate and locate prey.
Whistles are primarily used to communicate with other dolphins.
Burst-pulse sounds tend to occur when dolphins interact socially.
Listen to these clicks and repeating whistle by a Sarasota dolphin: Sarasota dolphin
Dive Deeper to learn about our dolphin communication experiments
A “click” is a small pulse of sound sent out from the dolphin’s head. If the click bounces off something, the dolphin hears it, much like you hear an echo of your voice in a canyon.
Click below to listen to dolphin clicks, which sound like running your fingers over a comb you use on your hair. You can also hear whistles which are produced simultaneously.
The dolphin’s brain may process the echo from up to hundreds of thousands of clicks each second (40-130 kHz). Researchers call this echolocation.
Echolocation helps dolphins to navigate in dark or murky water, to locate and capture their prey, and to detect predators.
Dolphin echolocation was first proven when trained dolphins demonstrated that they could navigate through an obstacle course with their eyes covered. Think how useful echolocation might be for finding and catching fast moving fish at night!
Dolphins may produce whistles that are specific to an individual. These whistles are termed “signature whistles.” They appear to be used to communicate the identity, location, and possibly the emotional state of the dolphin making the whistle.
Click below to hear different dolphin whistle patterns.
These whistles allow dolphins spread over hundreds of yards to maintain contact, even though the dolphins may not able to see one another.
Experiments conducted during SDRP health assessments have shown that dolphins can recognize the whistles of close relatives and known associates. This would be useful information for a dolphin that is swimming freely in the wild and socializing with other dolphins.
Dive deeper into research onDolphin Communication
Captive dolphins are often trained to surface and make noises for the audience. The noises sound like squawks. What we humans hear as squawking noises, though, is what scientists call a burst-pulse sound.
A burst-pulse is actually a closely grouped series of clicks [clicks above]. We are able to hear the burst pulses as squawks, which is unusual because many dolphins’ sounds are out of human hearing range.
The function of burst pulses is unclear. They tend to occur while several dolphins are interacting, so they may have a social function. Some researchers believe that wild dolphins may also use a different type of burst pulse to stun prey fish, but this is still an area of expanding research.
Relevant SDRP Citations
Sayigh, L.S. and V.M. Janik. 2009. Signature whistles. Pp. 1014-1016 In: W.F. Perrin, B. Würsig, and J.G.M. Thewissen, eds., Encyclopedia of Marine Mammals. Second Edition. Elsevier, Inc., San Diego, CA.
Sayigh, L.S., H.C. Esch, R.S. Wells, and V.M. Janik. 2007. Facts about signature whistles of bottlenose dolphins (Tursiops truncatus). Animal Behaviour 74:1631-1642.
Sayigh, L.S., P.L. Tyack, R.S. Wells, A.R. Solow, M.D. Scott and A.B. Irvine. 1999. Individual recognition in wild bottlenose dolphins: A field test using playback experiments. Animal Behaviour 57:41-50.
Sayigh, L.S., R.S. Wells and P.L. Tyack. 1993. Recording underwater sounds of free-ranging dolphins while underway in a small boat. Marine Mammal Science. 9(2):209-213.
Simard, P., Lace, N., Gowans, S., Quintana-Rizzo, E., Kuczaj, II., S. A., Wells, R. S., & Mann, D. A. (2011), Low frequency narrow-band calls in bottlenose dolphins (Tursiops truncatus): Signal properties, function, and conservation implications J. Acoust. Soc. Am. 130, 3068 DOI:10.1121/1.3641442