Local dive shop operators and fishermen report that rough-toothed dolphins (Steno bredanensis) are frequently encountered off the coast of Utila, Honduras, (16°05'46.5"N 86°55'47.8"W). Our observations suggest that at least some of these animals may constitute a resident population, although the extent of the resident group's home range has not been determined. Twenty-eight rough-toothed dolphins were identified using photo-identification techniques, 15 of which were re-sighted on two or more occasions. The 12 animals that were re-sighted four or more times were typically seen together, suggesting that they constitute a stable social group. At least one of these dolphins is an adult male, and his continued presence in this social group may reflect a social structure for rough-toothed dolphins that differs from that described for other dolphin species. Social interactions often involved tactile behaviours such as pectoral fin rubbing and side rubbing. The observed dolphins sometimes expressed interest in the research vessel and other boats by approaching, and on separate occasions examined a hydrophone and slow moving propeller visually and echoically. Overall, our behavioural observations suggest: (1) synchronous behaviours and ‘tight’ groupings are common while rough-toothed dolphins are travelling; (2) tactile contact is an important aspect of social interactions for rough-toothed dolphins; (3) cooperative behaviour occurs during play; and (4) rough-toothed dolphins are curious.

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-The repertoire of socio-sexual and sexual behaviors of cetaceans is relatively unknown. The purpose of the current study was to advance the existing knowledge of socio-sexual behavior of beluga whales through the development of a behavioral catalog that lists the full repertoire of sexual and socio-sexual behaviors. A behavioral catalog was developed initially from 800 hours of observations, collected across a 7-year period from 11 belugas ranging in age (birth to 30+ years), sex, and social groupings. Using this behavioral catalog, observations of eight additional belugas housed between two other facilities were coded for socio-sexual and sexual behaviors. Sociosexual and sexual behaviors of belugas were similar across all three facilities. Socio-sexual and sexual behaviors involved sequenced behaviors, had lateralized components, and were often subtle in nature. Some of these behaviors overlapped with potentially aggressive actions but showed distinct differences in their form, or topography. Complexity and duration of socio-sexual interactions varied depending on the age and sex of the participating belugas. The development of a complete behavioral catalog, or ethogram, of the socio-sexual and sexual behaviors has profound influences on understanding the mechanisms involved for successful reproduction, a problem that several groups of belugas in their natural habitat are currently facing.Keywords -Beluga, Socio-sexual behavior, Sexual behavior, Behavioral repertoire, Delphinapterus leucas Socio-sexual behavior has been studied in terms of reproductive success, copulation, and courtship. Reproductive success and copulation rates are relatively easy to identify if the definition includes documenting pregnancies, births, and intromission attempts between sexually-mature and receptive individuals. These behaviors, which are directly related to conception or involve direct stimulation of genitalia, can be defined with the term sexual (Campbell, 2007;Connor, Read, & Wrangham, 2000;Connor, Wells, Mann, & Read, 2000). In comparison, socio-sexual behavior includes behaviors that may not be directly involved in conception but may be used for other social purposes, such as developing and maintaining relationships between individuals or courtship (Campbell, 2007;Connor, Wells, et al., 2000). Courtship has traditionally been defined as the innate set of behaviors performed prior to copulation (Lorenz, 1958;Tinbergen, 1952). More recently, the definition of courtship has been expanded to include both elicited innate and emitted learned stereotyped behaviors that draw the attention of potential mates (reviewed by Freeberg, 2000). Hill et al. 106A review of general research on animal behavior indicated that sexual and socio-sexual interactions were the least studied area of research (27% of articles reviewed, Hill, Artz, & Lopez, 2014). Most studies of socio-sexual and sexual interactions have been conducted primarily with fish, amphibians, and invertebrates in laboratory settings. The sexual and socio-sexual behav...

Lateralization of cognitive processes and motor functions has been demonstrated in a number of species, including humans, elephants, and cetaceans. For example, bottlenose dolphins (Tursiops truncatus) have exhibited preferential eye use during a variety of cognitive tasks. The present study investigated the possibility of visual lateralization in 12 belugas (Delphinapterus leucas) and six Pacific white-sided dolphins (Lagenorhynchus obliquidens) located at two separate marine mammal facilities. During free swim periods, the belugas and Pacific white-sided dolphins were presented a familiar human, an unfamiliar human, or no human during 10-15 min sessions. Session videos were coded for gaze duration, eye presentation at approach, and eye preference while viewing each stimulus. Although we did not find any clear group level lateralization, we found individual left eye lateralized preferences related to social stimuli for most belugas and some Pacific white-sided dolphins. Differences in gaze durations were also observed. The majority of individual belugas had longer gaze durations for unfamiliar rather than familiar stimuli. These results suggest that lateralization occurs during visual processing of human stimuli in belugas and Pacific white-sided dolphins and that these species can distinguish between familiar and unfamiliar humans.

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