A bottlenose dolphin (Tursiops truncatus) demonstrated the ability to select the matching object in a matching-to-sample task after listening to another dolphin inspect the sample object via echolocation. The listener was prevented from inspecting the sample himself. In Experiment 1, with objects familiar to both dolphins, the listener's performance was significantly better than chance. In Experiment 2, objects familiar to only one of the dolphins were used. On these trials, the listener's performance was significantly better than chance only when the inspecting dolphin made a correct choice. Analysis of the listener's responses when the inspector made an error demonstrated that this contingency was not due to the listener's matching the inspector's response, but was apparently due instead to inadequate information in the echo. The results suggest that the listener was able to "eavesdrop" on echoes produced by the inspector's clicks and derive characteristics of the sample object.
In 2001, Xitco et al. (Anim Cogn 4:115-123) described spontaneous behaviors in two bottlenose dolphins (Tursiops truncatus) that resembled pointing and gaze alternation. The dolphins' spontaneous behavior was influenced by the presence of a potential receiver, and the distance between the dolphin and the receiver. The present study adapted the technique of Call and Tomasello [(1994) J Comp Psychol 108:307-317], used with orangutans to test the effect of the receiver's orientation on pointing in these same dolphins. The dolphins directed more points and monitoring behavior at receivers whose orientation was consistent with attending to the dolphins. The results demonstrated that the dolphins' pointing and monitoring behavior, like that of apes and infants, was linked to the attentional behavior of the receiver.
Animal managers from three institutions that holdTursiops truncatus participated in a workshop directed at documenting survivability of Tursiops neonates (birth to 30 d of age) in their managed populations. Key information was generated for the period 1990 through 2009 for the three organizations. Included in the findings are (1) documentation of the total live births, total fatalities, and causal factors of neonate losses; (2) recommendations for optimizing animal management procedures through standardized monitoring and husbandry intervention techniques, resulting in the best possible survivability of neonates; and (3) comparison of neonate survivability between the years 1990 to 1999 (78.2% of live births) and 2000 to 2009 (90.6% of live births), the latter decade representing progressing improvements in survivability resulting from recommended animal management procedures.
Objective-To evaluate annual survival and mortality rates and the longevity of a managed population of bottlenose dolphins (Tursiops truncatus). Design-Retrospective cohort study. Animals-103 bottlenose dolphins at the US Navy Marine Mammal Program (MMP). Procedures-Population age structures, annual survival and crude mortality rates, and median age at death for dolphins > 30 days old were determined from 2004 through 2013. Results-During 2004 through 2013, the annual survival rates for MMP dolphins ranged from 0.98 to 1.0, and the annual crude mortality rates ranged from 0% to 5%, with a mean of 2.7%. The median age at death was 30.1 years from 2004 through 2008 and increased to 32 years from 2009 through 2013. The maximum age for a dolphin in the study was 52 years. Conclusions and Clinical Relevance-Results indicated that the annual mortality rates were low and survival rates were high for dolphins in the MMP from 2004 through 2013 and that the median age at death for MMP dolphins during that time was over 10 years greater than that reported in free-ranging dolphins. These findings were likely attributable to the continually improving care and husbandry of managed dolphin populations.
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