Embedded Files
Dolphins whistle their names to communicate with other dolphins. Because each dolphin has its own, unique "signature whistle," scientists can use special equipment to listen under water and identify different dolphins by the sounds of their whistles. Dolphin researchers have collected spectrograms, or "sound pictures," showing the frequencies, amplitude, and wavelengths of over 269 dolphin whistles. Spectrograms can be matched to the sounds of dolphin whistles recorded underwater. By identifying dolphin whistles, scientists can determine where and how far individual dolphins travel and estimate the locations and range that different dolphin communities occupy.
Map from: Tyson Moore, Reny & Urian, Kim & Allen, Jason & Cush, Carolyn & Parham, Jason & Blount, Drew & Holmberg, Jason & Thompson, Jamie & Wells, Randall. (2022). Rise of the Machines: Best Practices and Experimental Evaluation of Computer-Assisted Dorsal Fin Image Matching Systems for Bottlenose Dolphins. Frontiers in Marine Science. 9. 849813. 10.3389/fmars.2022.849813., p. 4. (Numbers added for this activity.)
To learn more about the PALS network, visit the Sarasota Bay Dolphin Research Program (SDRP) website.
Research Challenge:
Identify Dolphins Using Signature Whistles
The Sarasota Bay Listening Network (SBLN) is made up of coastal hydrophones that continuously record underwater sounds. Through this network, researchers monitor sound-producing animals, including bottlenose dolphins, fish, and other ocean wildlife.
Six different dolphin signature whistles were recorded at five passive acoustic listening station (PALS) land-based hydrophone stations (numbered 1-5) during the month of January. The whistles for these six different unknown dolphins were labeled "A, B, C, D, E, and F."
Could dolphins A-F include any of the following dolphins?
Mabel /F197 Perry/FB20
Ginger/F211 Wasabi/F264
Maddie/F213 No Name Assigned/F320
To find out, scroll down to listen to whistles from unidentified dolphins A-F recorded at PALS stations 1-5. See if you can match these whistles to the spectrograms from the Sarasota Whistle Database shown below.
**A spectrogram is a picture that shows a sound's frequency and amplitude over time. Would you like to see how a spectrogram works? Try this online, interactive spectrogram from Listening to Waves, created by a team led by Victor Minces and funded by the National Science Foundation.
Directions for Identifying Dolphin Whistles
The chart to the left below includes whistles of dolphins A-F recorded at PALS stations that are part of SBLN. Press the button next to each unidentified dolphin (A-F) to hear a recording of its whistle. Then, see if you can match the whistle to one of the six spectrograms on the right. (Use the arrows on the spectrograms to view the different spectrograms.)
Answers on About page
To learn more about the Sarasota Dolphin Whistle Data Base, read "Whistling Away in Sarasota Bay" on the SDRP Website.
Whistle Database Spectrograms
X-axis: Time (in seconds)
Y-axis: Soundwave Frequency (higher pitches have higher frequencies.) Dolphin whistle frequencies typically fall between 7kHz and 15 kHz.
Amplitude (volume) is shown with color. Yellow-Red = loud-very loud; Green-Blue= soft-very soft
Acknowledgement: Whistle recordings are available thanks to Dr. Laela Sayigh, Manager, Sarasota Dolphin Whistle Database, Woods Hole Oceanographic Institute.
Click the drop-down arrow for written descriptions of the whistles depicted in the spectrograms above.
A single loop whistle consists of a single, non-repeated element, or piece.
Whistles with multiple elements (or pieces) are called multi-loop whistles. These loops can all be alike or curve shapes can vary.
A multi-loop with a break, or brief silence, between elements are disconnected.
If a multi-loop whistle does not have silence between elements, it is connected.
The fundamental frequency is the lowest frequency curve, or outline, on the spectrogram. (The curves above the lowest frequency are harmonics.) Typically, the fundamental frequency for whistle signatures of bottlenose dolphins falls between 7 KHz and 15 kHz.
Whistles can have periods of constant frequency, where the frequency does not rise or fall.
Whistles can show an upsweep, where the frequency gets higher, or a down-sweep, where the frequency gets lower.
Spectrogram colors show amplitude, or volume. Bright colors such as yellow or red show high amplitudes, or louder volumes. Greens and blues indicate lower amplitudes, or softer volumes.
Here are descriptions of dolphin signature whistles A-F:
Dolphin A Whistle: The whistle is disconnected and multi-loop. There is an extended period of an almost constant frequency and the whistle ends in a down-sweep.
Dolphin B Whistle: This whistle is a single loop whistle that ends in an upsweep. Lower frequencies can be heard intermittently as well.
Dolphin C Whistle: The whistle is a disconnected, multi-loop whistle. The introductory (first) loop includes low frequency pulses with a high amplitude and is followed by two upsweeps.
Dolphin D Whistle: This multi-loop whistle is composed of two disconnected elements, each ending in a down-sweep. Low frequency, high amplitude sounds are present as the second loop concludes.
Dolphin E Whistle: This multi-loop whistle has four disconnected loops with baseline frequencies ranging approximately between 6 and 10 kHz.
Dolphin F Whistle: The whistle inlcudes four connected loops with baseline frequencies ranging between approximately 5 and 10.
Page updated
Report abuse