Biology Data Sets
Permanent URI for this collection
Browse
Browsing Biology Data Sets by Subject "Bottlenose dolphin"
Results Per Page
Sort Options
-
DatasetBottlenose dolphin mothers modify signature whistles in the presence of their own calves(Woods Hole Oceanographic Institution, 2023-05-22) Sayigh, Laela S. ; El Haddad, Nicole ; Tyack, Peter L. ; Janik, Vincent M. ; Jensen, Frants H. ; Wells, Randall S.Human caregivers interacting with children typically modify their speech in ways that promote attention, bonding and language acquisition. Although this “motherese,” or child-directed communication (CDC), occurs in a variety of human cultures, evidence among non-human species is very rare. We looked for its occurrence in a non-human mammalian species with long-term mother-offspring bonds that is capable of vocal production learning, the bottlenose dolphin (Tursiops truncatus). Dolphin signature whistles provide a unique opportunity to test for CDC in non-human animals, because we are able to quantify changes in the same vocalizations produced in the presence or absence of calves. We analyzed recordings made during brief catch-and-release events of wild bottlenose dolphins in waters near Sarasota Bay, Florida, USA, and found that females produced signature whistles with significantly higher maximum frequencies and wider frequency ranges when they were recorded with their own dependent calves vs. not with them. These differences align with the higher fundamental frequencies and wider pitch ranges seen in human CDC. Our results provide the first evidence in a non-human mammal for changes in the same vocalizations when produced in the presence vs. absence of offspring, and thus strongly support convergent evolution of motherese, or child-directed communication, in bottlenose dolphins. CDC may function to enhance attention, bonding and vocal learning in dolphin calves, as it does in human children. Our data add to the growing body of evidence that dolphins provide a powerful animal model for studying the evolution of vocal learning and language.
-
DatasetFirst evidence for widespread sharing of stereotyped non-signature whistle types by wild dolphins(Woods Hole Oceanographic Insitution, 2024-07-30) Sayigh, Laela S. ; Janik, Vincent M. ; Jensen, Frants H. ; McHugh, Katherine ; Tyack, Peter L. ; Wells, Randall S.Bottlenose dolphins (Tursiops truncatus) have long fascinated animal communication researchers due to their large brains and varied communicative signals. However, studying dolphin communication is challenging due to difficulties in identifying which individual is making a sound. A long-term study of a resident population of free-ranging dolphins in waters near Sarasota, Florida, employs brief catch-and-release as a research tool for health assessments, and this has enabled us to obtain high-quality recordings of known individual dolphins for 4 decades. We have a catalog of the individually distinctive signature whistles (SW) of most animals in the community; these referential signals function much like human names. Whistles other than the signature, known as “non-signature whistles” (NSW) are very poorly understood. We are building a catalog of stereotyped NSWs that are shared by more than one individual, and have so far identified more than 20 shared NSW types, two of which were produced by at least 25 different individuals. These whistles were recorded both during health assessments and from free-swimming dolphins wearing non-invasive, suction-cup attached digital acoustic tags (DTAGs), which we are able deploy on dolphins prior to release. We have embarked on playback studies to study the functions of both SW and shared NSW, in which we film movement responses with drones and record vocal responses with hydrophones and DTAGs. Control trials (n=21), in which we played the target dolphin’s own SW, elicited approach in 76% of trials in which we were able to observe the response. These data support the affiliative nature of SW copies, which appear to function as a way to initiate contact with another individual. Playbacks of a widely shared NSW, NSWA (n=8 trials), consistently elicited avoidance responses (100% of 6 observed trials) , suggesting an alarm or warning type function. Another widely shared NSW, NSWB, has elicited varying responses in 8 trials, depending on the age and sex of the target dolphin. NSWB was also produced by the target dolphin in response to 2 playback trials. Our suggested function of NSWB is a “query”- type whistle, produced when something unexpected or unfamiliar is heard. In this case, we would expect different responses depending on age and sex class, for example with males likely being more interested in exploring unfamiliar stimuli than females with calves. Overall, this research presents the first evidence for shared, stereotyped, context-specific whistles in bottlenose dolphins, and suggests that NSWs play an important role in the dolphin communication system.