Vocal correlates of arousal in bottlenose dolphins (Tursiops spp.) in human care

Abstract

Human-controlled regimes can entrain behavioural responses and may impact animal welfare. Therefore, understanding the influence of schedules on animal behaviour can be a valuable tool to improve welfare, however information on behaviour overnight and in the absence of husbandry staff remains rare. Bottlenose dolphins (Tursiops spp.) are highly social marine mammals and the most common cetacean found in captivity. They communicate using frequency modulated signature whistles, a whistle type that is individually distinctive and used as a contact call. We investigated the vocalisations of ten dolphins housed in three social groups at uShaka Sea World dolphinarium to determine how patterns in acoustic behaviour link to dolphinarium routines. Investigation focused on overnight behaviour, housing decisions, weekly patterns, and transitional periods between the presence and absence of husbandry staff. Recordings were made from 17h00 – 07h00 over 24 nights, spanning May to August 2018. Whistle (including signature whistle) presence and production rate decreased soon after husbandry staff left the facility, was low over night, and increased upon staff arrival. Results indicated elevated arousal states particularly associated with the morning feeding regime. Housing in the pool configuration that allowed observation of staff activities from all social groups was characterised by an increase in whistle presence and rates. Heightened arousal associated with staff presence was reflected in the structural characteristics of signature whistles, particularly maximum frequency, frequency range and number of whistle loops. We identified individual differences in both production rate and the structural modification of signature whistles under different contexts. Overall, these results revealed a link between scheduled activity and associated behavioural responses, which can be used as a baseline for future welfare monitoring where changes from normal behaviour may reflect shifts in welfare state.

Antillean manatee calves in captive rehabilitation change vocal behavior in anticipation of feeding

“…For example, bottlenose dolphins demonstrate various anticipatory changes in behavior (Clegg & Delfour, 2018a; 2018b; Jensen et al, 2013) including increasing the production of calls and altering the structure of whistles when staff were present. These behavioral changes support a link between scheduled feeding activity and dolphin vocal behavior (Probert et al, 2021). Similarly, captive false killer whales ( Pseudorca crassidens ) increased call rates before feeding times and decrease call rates immediately after feeding sessions (Platto et al, 2016).…”

“…Stump‐tailed macaques ( Macaca arctoides ) increased rates of abnormal behaviors and vocalizations before scheduled feeding times (Waitt & Buchanan‐Smith, 2001). Vocalizations are linked to the emotional states of animals and associating changes in vocal activity can also indicate anticipatory behavior (Probert et al, 2021). For example, bottlenose dolphins demonstrate various anticipatory changes in behavior (Clegg & Delfour, 2018a; 2018b; Jensen et al, 2013) including increasing the production of calls and altering the structure of whistles when staff were present.…”

“…Stump-tailed macaques (Macaca arctoides) increased rates of abnormal behaviors and vocalizations before scheduled feeding times (Waitt & Buchanan-Smith, 2001). Vocalizations are linked to the emotional states of animals and associating changes in vocal activity can also indicate anticipatory behavior (Probert et al, 2021).…”

“…The bottom spectrogram shows a high squeak following by a squeak. Spectrograms were generated in Raven 1.6 (Center for Conservation Bioacoustics, 2021) with the following parameters: DFT: 1024; Hamming window; overlap: 80% (color).two frequency intervals of equal energy since animals can shift frequency parameters of their vocalizations in different behavioral contexts(Probert et al, 2021). Calls were classified into five categories followingBrady et al (2021): squeak, high-squeak, squeak-squeal, squeal, and chirps.…”

Molecular Assessments, Statistical Effectiveness Parameters and Genetic Structure of Captive Populations of Tursiops truncatus Using 15 STRs

“…Each assignment shows morphological, demographic, spatial, temporal, and genetic differences [ 6 ]. Given its social capacity, T. truncatus is one of the most used animals in the recreational industry and assisted therapy, being one of the most widely distributed specimens in captivity [ 7 ]. In addition, research programs have included specimens living as captives to enrich the knowledge about their social lives, communication, cognitive development, natural ecology, and feeding habits, among others [ 8 , 9 , 10 ].…”