Reactions of three bottlenose dolphin dams with calves to other members of the group in connection with nursing

The suckling behavior of three bottlenose dolphin (Tursiops truncatus) mother–calf pairs at the Kolmården Wild Animal Park, Sweden, was followed from birth until the calves were 1 year old, with emphasis on the behavior of the mothers toward other dolphins present in pool. The results show that 80.44% of the sucklings occurred when the dams were not accompanied by another member of the group. This preference declined, as the calf grew older, for all three dams. Three factors influenced this company preference in relation to nursing and contributed to the total variance in a detectable way: the month post partum, company preference, and the mother's ID, i.e., which mother was involved. The time between the category “dam leaves company” and the beginning of nursing increased over the months for all three dams. These results indicate that another dolphin is not automatically an asset to a dam with a newborn, and that, in human care, ample space and limited number of pool mates must be provided to allow the dam the necessary privacy in connection with nursing. Zoo Biol 0:1–13, 2005. © 2005 Wiley‐Liss, Inc.     

Brays and bits: information theory applied to acoustic communication sequences of bottlenose dolphins

Acoustic call sequences are important components of vocal repertoires for many animal species. Bottlenose dolphins (Tursiops truncatus) produce a wide variety of vocalizations, in different behavioural contexts, including some conspicuous vocal sequences – the ‘bray series’. The occurrence of brays is still insufficiently documented, contextually and geographically, and the specific functions of these multi-unit emissions are yet to be understood. Here, acoustic emissions produced by bottlenose dolphins in the Sado estuary, Portugal, were used to provide a structural characterization of the discrete elements that compose the bray series. Information theory techniques were applied to analyse bray sequences and explore the complexity of these calls. Log-frequency analysis, based on bout criterion interval, confirmed the bout structure of the bray series. A first-order Markov model revealed a distinct pattern of emission for the bray series’ elements, with uneven transitions between elements. The order in these sequential emissions was not random and consecutive decreases in higher order entropy values support the notion of a well-defined structure in the bray series. The key features of animal signal sequences here portrayed suggest the presence of relevant information content and highlight the complexity of the bottlenose dolphin’s acoustic repertoire.     

A METHOD FOR CALCULATING THE EFFECT OF A DIE-OFF FROM STRANDING DATA

A method was developed for estimating the mortality during a die-off of marine mammal species from longitudinal stranding data. A deterministic mathematical model of the stranding process was used to calculate the mortality during a die-off. The model incorporated natural and anthropogenic mortality rates, the number of stranded carcasses before, during, and after the die-off, the duration of the die-off, and detection probability of a stranded carcass. The model was applied to data for the bottlenose dolphin ( Tursiops truncatus ) along the Atlantic coast of the United States. The mortality rate during the epizootic of 1987 and 1988 was calculated using the model. Sensitivity analyses indicated that precise estimates of natural and anthropogenic mortality rates were important for obtaining precise additional mortality rates during the die-off. For stranding data to be useful in this model, data should be collected in a consistent manner and effort within a defined area prior to, throughout, and after a die-off. Survey effort also should be measured.     

Free flight capacity determination in a sustained flight tunnel: effects of age and sexual state on the flight duration of Prostephanus truncatus

Abstract. . Adult Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) steering anemotactically upwind to a pheromone source in a wind tunnel, respond normally to, and alter their ground speed according to the direction and speed of, the movement of ground patterns beneath them. By manipulating this optomotor reaction component of their behaviour, studies were conducted on their flight duration. The results show a great deal of individual variation in flight duration, and the general data on single flights were skewed towards short flights. Pre-reproductive and inter-reproductive male and female beetles flew significantly longer than older beetles that had passed their peak of reproduction. There was no significant difference in the flight duration of male and female beetles at any age. The overall results suggest mat younger P. truncatus are capable of long-distance flights, and support the proposition that flight could be important in the spread of the beetle.     

Interrelationship of molluscicidal concentration and temperature on the respiration of Bulinus truncatus

The oxygen consumption of Bulinus truncatus subjected to two molluscicides was tested at different temperatures and different concentrations. The most effective combination for field application was discussed.     

CYCLIC OCULAR HYPERTENSION IN CETACEANS

In the laboratory, intraocular pressure (IOP) was measured in each eye of two adult Tursiops truncatus and one Grampus griseus . Measures were made in alternation between eyes over a time span. Means and standard deviations were calculated. Mean IOP's ranged from 33.4 mm Hg (SD = 2.4) in the male Tursiops to 24.6 (SD = 2.3) in the female Tursiops . IOP in the Grampus was intermediate. Tonograph functions for the Tursiops over periods greater than 25 min had a cyclic character with maxima and minima. These cycles were fitted with a polynomial function with periods of 15 min (female) and 20 to 26 min (male). There was no significant correlation of the IOP variations with time between eyes in either Tursiops . Compared to humans, these cetaceans exhibit clinical ocular hypertension bilaterally. The range of pressures they exhibit, over time, is much greater than reported previously for several terrestrial mammals.     

Epidemiology of tattoo skin disease in captive common bottlenose dolphins (Tursiops truncatus): Are males more vulnerable than females?

Clinical and epidemiological features of tattoo skin disease (TSD) are reported for 257 common bottlenose dolphins held in 31 facilities in the Northern Hemisphere. Photographs and biological data of 146 females and 111 males were analyzed. Dolphins were classified into three age classes: 0–3 years, 4–8 years, and older than 9 years. From 2012 to 2014, 20.6% of the 257 dolphins showed clinical TSD. The youngest dolphins with tattoo lesions were 14 and 15 months old. TSD persisted from 4 to 65 months in 30 dolphins. Prevalence varied between facilities from 5.6% to 60%, possibly reflecting variation in environmental factors. Unlike in free-ranging Delphinidae, TSD prevalence was significantly higher in males (31.5%) than in females (12.3%). Infection was age-dependent only in females. Prevalence of very large tattoos was also higher in males (28.6%) than in females (11.1%). These data suggest that male T. truncatus are more vulnerable to TSD than females, possibly because of differences in immune response and susceptibility to captivity-related stress.