“I did it!” – Dolphins cheer for themselves

Dolphins may call success and squeal in victory when completing a task correctly or catching prey.

Dolphins emit different types of vocalizations to transmit information about food, location and emotional state. One type of vocalization is called a “burst pulse”. Burst pulse signals are considered rapid click trains and have been observed when dolphins are foraging, as well as socializing.

Victory squeal with a simultaneous whistle. (Ridgway et al., 2015)
Victory squeal. (Ridgway et al., 2014)

Dr. Ridgway and colleagues conducted a unique study that combined simultaneous video and acoustic recordings to investigate what behaviors and vocals dolphins used when attempting to capture prey.

Researchers and trainers used a natural sea pen where a dolphin and trainer stayed at one end of the enclosure, while a fish was baited at the opposite end. Once the trainer cued the dolphin, it would swim across the enclosure in search of the fish.

A unique device was utilized in order to visually record the animal’s physical and acoustic behaviors at the same time. The device was temporarily placed on the melon (i.e., the top of the dolphin’s head) along with an additional hydrophone near the baited fish.

Customized device that simultaneously documented visual and audio recordings.

The researchers found a unique, 3-part vocal pattern during prey capture:

  1. Echolocation clicks were used to search out the fish,
  2. Clicks became closer together as the dolphin neared the fish
  3. A victory squeal (VS) (i.e., burst pulse signal) was emitted at (or just before) the time of capture
(A) As the dolphin eats the fish, head jerks are recorded on the forehead camera microphone. (B) Beginning of approach, echolocation clicks are found; the inter-click-interval became smaller when closing in on fish; at capture, victory squeal was emitted (C) Left to right: (a) view from forehead camera of fish (white arrow) in the distance (b) closing in on fish, TB (c) view of fish in dolphin’s mouth and simultaneous victory squeal (d) view of dolphin rostrum as the animal moves away clicking. (D) spectrogram of vocal pattern emitted during prey capture (from approach to just after capture).

Researchers coined the term “Victory Squeal” to represent the context of when it occurs (when a dolphin knows it has/or is about to succeed in a task), and the vocal being reminiscent of a child-like squeal.

This study was the first of its kind – connecting video and audio at the same time. Researchers were able to confirm dolphins using head jerking behavior when they are consuming a fish. They also presented a particular vocal sequence used when successfully capturing prey. They even extended their research and found that dolphins used a VS when doing a request from their trainer correctly!

Research in the future could potentially use this vocal pattern to assume successful behaviors in managed care or in the wild when people are unable to visualize what the dolphins are doing.

Dive into their study here and find out more about their investigation.