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Old Mystic, CT, United States

Levengood A.L.,University of St. Andrews | Levengood A.L.,University of The Sunshine Coast | Dudzinski K.M.,Dolphin Communication Project
Behavioural Processes | Year: 2016

Relationships are important for social animals and kinship can play a vital role. Still, occurrence and function of kin bonds (aside from mother) in delphinid calf associations, alloparenting, or calf rearing are poorly represented in the literature. This study examined the role of kin and non-kin in non-mother-calf associations for a managed population of bottlenose dolphins. Calf associations were event sampled to determine if kin and non-kin differences existed in frequency or duration. Calves with kin present exhibited a higher average number of associates than calves without kin. Yet calves showed no conclusive association preference in frequency; though some individuals showed early signs of developing kin preferences. Duration and context of associations did not differ between kin and non-kin, suggesting they serve the same developmental purpose. However, personality, calf age, and associate age played a greater role in the formation of calf associations, supporting the notion that calves choose associates with similar traits, aiding in their development in difficult and changing environments. Though kinship is important in the formation of relationships in older dolphins, it appears that outside the mother-calf bond, there are other more influential factors, such as age, personality, and sociality in the formation of early developmental bonds. © 2015 Elsevier B.V. Source

Evans-Wilent J.,Connecticut College | Dudzinski K.M.,Dolphin Communication Project
Behavioural Processes | Year: 2013

Pectoral fin contact in bottlenose dolphins represents one form of tactile communication. Acoustic communication associated with pectoral fin contact is an additional level of communication that may change or enhance the tactile message between two individuals. In this study, we examine vocalization types associated with pectoral fin contact in a group of captive bottlenose dolphins (. Tursiops truncatus). From 2006 to 2009, vocalizations potentially associated with 748 pectoral fin contacts were examined: whistles, click trains and overlap of whistles and click trains were documented when associated with fin contact. Dolphins were also documented not vocalizing when exchanging pectoral fin contacts. Call type associated with pectoral fin contact was compared for the proportion of the type of pectoral fin contact, vocalizer sex, initiator and receiver roles, and gender pair. Overall, vocalizations differed significantly by vocalizer role as rubber or rubbee, initiator, and sex. Receivers and rubbees clicked and used overlap vocalizations more frequently, and males produced overlap vocalizations more frequently. These results suggest that whistles may be used to initiate pectoral fin contact or show preference for a particular partner, while click trains may be used to show disinterest in pectoral fin contact or to signal the end of a contact. Examining vocalizations produced in conjunction with tactile contact is a relatively new approach in the study of individual dolphin behavior and may be useful for understanding dolphin social alliances and social preferences for various individuals within a population. © 2013 Elsevier B.V. Source

Vaughn-Hirshorn R.L.,Texas A&M University at Galveston | Hodge K.B.,Texas A&M University at Galveston | Hodge K.B.,Cornell University | Wursig B.,Texas A&M University at Galveston | And 3 more authors.
Journal of the Acoustical Society of America | Year: 2012

Dusky dolphin (Lagenorhynchus obscurus) acoustic sounds were characterized by analyzing narrowband recordings [0-16 kHz in New Zealand (NZ) and 0-24 kHz in Argentina], and sounds in broadband recordings (0-200 kHz) were compared to their counterparts in down-sampled narrowband recordings (0-16 kHz). The most robust similarity between sounds present in broadband recordings and their counterparts in the down-sampled narrowband recordings was inter-click interval (ICI); ICI was therefore primarily used to characterize click sounds in narrowband recordings. In NZ and Argentina, distribution of ICIs was a continuum, although the distribution of ICIs in NZ had a somewhat bimodal tendency. In NZ, sounds that had smaller mean ICIs were more likely to have constant ICIs, and less likely to have increasing or decreasing ICIs. Similar to some other delphinids, dusky dolphins may use single, short duration sounds that have a constant ICI and closely spaced clicks for communication. No whistles were documented at either study site. Temporally structured sequences of burst pulses (i.e., sounds with ICI < about 10 ms) also occurred at both study sites, and these sequences contained 2-14 burst pulses that appeared closely matched aurally and in spectrograms and waveforms. © 2012 Acoustical Society of America. Source

Vaughn-Hirshorn R.L.,Texas A&M University at Galveston | Muzi E.,Texas A&M University at Galveston | Richardson J.L.,Texas A&M University at Galveston | Fox G.J.,Texas A&M University at Galveston | And 4 more authors.
Behavioural Processes | Year: 2013

We characterized dusky dolphin (Lagenorhynchus obscurus) feeding behaviors recorded on underwater video, and related behaviors to variation in prey ball sizes, dolphin group sizes, and study site (Argentina versus New Zealand, NZ). Herding behaviors most often involved dolphins swimming around the side or under prey balls, but dolphins in Argentina more often swam under prey balls (48% of passes) than did dolphins in NZ (34% of passes). This result may have been due to differences in group sizes between sites, since groups are larger in Argentina. Additionally, in NZ, group size was positively correlated with proportion of passes that occurred under prey balls (p<0.001). Prey-capture attempts most often involved capturing fish from the side of prey balls, but dolphins in Argentina more often swam through prey balls (8% of attempts) than did dolphins in NZ (4% of attempts). This result may have been due to differences in prey ball sizes between sites, since dolphins fed on larger prey balls in Argentina (>74m2) than in NZ (maximum 33m2). Additionally, in NZ, dolphins were more likely to swim through prey balls to capture fish when they fed on larger prey balls (p=0.025). © 2013 Elsevier B.V. Source

Dudzinski K.M.,Dolphin Communication Project | Dudzinski K.M.,University of Southern Mississippi | Gregg J.D.,Dolphin Communication Project | Paulos R.D.,Dolphin Communication Project | And 2 more authors.
Behavioural Processes | Year: 2010

Tactile exchanges involving the pectoral fin have been documented in a variety of dolphin species. Several functions (e.g., social, hygienic) have been offered as possible explanations for when and why dolphins exchange pectoral fin contacts. In this study, we compared pectoral fin contact between dolphin dyads from three distinct dolphin populations: two groups of wild dolphins; Atlantic spotted dolphins (Stenella frontalis) from The Bahamas and Indo-Pacific bottlenose dolphins (Tursiops aduncus) from around Mikura Island, Japan; and one group of captive bottlenose dolphins (Tursiops truncatus) residing at the Roatan Institute for Marine Sciences, Anthony's Key Resort. A number of similarities were observed between the captive and wild groups, including; rates of pectoral fin contact, which dolphin initiated contact, posture preference, and same-sex rubbing partner preference. Unlike their wild counterparts, however, dolphins in the captive study group engaged in petting and rubbing at equal rates, females were more likely to contact males, males assumed the various rubbing roles more frequently than females, and calves and juveniles were more likely to be involved in pectoral fin contact exchanges. These results suggest that some aspects of pectoral fin contact behaviour might be common to many dolphin species, whereas other aspects could be species specific, or could be the result of differing environmental and social conditions. © 2010 Elsevier B.V. Source

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