Inter-observer reliability is also possible from videotaped records, thus providing a set of observations able to withstand the rigors of statistical machinations. Video recordings are especially useful for documentation, and subsequent analysis, of subtle within-group signaling of dolphins underwater, where they spend over 85% of their time. More importantly, comparisons of specific behaviors between individuals and groups of dolphins are facilitated. These data can be analyzed for evidence of acoustic, visual, and tactile signal exchange and behavioral coordination within varying social contexts. Observations of dolphin behavior are enhanced through the use of video recordings valuable information is preserved and the dynamics of inter-animal relations, associations, behavior, and sociality can be examined. Location of the vocalizing dolphin is based upon associating visual distribution of animals with directions to sound sources as determined by aural psycho-acoustics.ĭudzinski and Gregg both used an ECD – echolocation click detector – that was added to the original design in a small second housing containing a digital audio (or recently an M-Audio) recorder together with a pre-processor circuit that allowed detection of the highly directional part of a dolphin’s echolocation ‘clicks’ and makes these audible and recordable.ĭudzinski affectionately calls the MVA her “array”–since it contains at least two hydrophones. Hydrophone spacing on the housing is scaled to the human inter-aural distance based upon the speed of sound in water (4.5 times faster than in air). Manually operated under water, the system consists of two omni-directional hydrophones cabled through a custom underwater housing into a stereo video camera. The mobile video/acoustic system (MVA) was developed to permit real-time synchronous recording of the sounds and behaviors of individual, free-swimming dolphins. Underwater observations of dolphins that are greater than 180 s become true encounters by definition > Short Encounter – Any underwater observations of dolphins between 30 s & 180 s. Spatially, each individual in a single subgroup is within at least five dolphin-body widths of its nearest conspecific. > Subgroup – Dolphins observed in apparent association, moving in the same general direction, although not all individuals necessarily heading in the same direction, and engaged in the same activity. At Mikura, the long axis placed parallel to the coastline. > Group – The “total available dolphins” observed within an imaginary ellipse, with a 200 m long axis & 100 m short axis for dimensions. A mobile video/acoustic system (MVA) is used to record dolphin behavior and sound. Simultaneous video and stereo audio recording of identified dolphins and real-time, all-occurrence documentation of specific behaviors and group activity provide a data record. Ridgway was very proud of these findings and was ecstatic to know that this culmination was going to be published in PLOS ONE," Brittany Jones, a scientist at the National Marine Mammal Foundation who worked with the study authors while they completed their paper, told Insider in an email.Focal animal and focal group follows provide the framework for data collection focusing on dolphin signal exchange and contact behavior. A paper about the footage was published in PLOS ONE in August 2022. For the first time, Ridgway and his team captured up-close video and sound of dolphins hunting and eating live fish. These videos are one of his final research efforts. He dedicated his entire career to understanding the behavior, physiology, and health of ocean mammals - especially bottlenose dolphins. He also founded and led the National Marine Mammal Foundation, the nonprofit behind the new paper.
That's the program that trained the dolphins in this study.
Ridgway helped found the US Navy's Marine Mammal Program more than 60 years ago. US Navy/National Marine Mammal Foundation Sam Ridgway was known as the father of marine-mammal science. Account icon An icon in the shape of a person's head and shoulders.
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