Developing a Catalog of Socio-Sexual Behaviors of Beluga Whales (Delphinapterus leucas) in the Care of Humans

Abstract

-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...

Socio-sexual and probable mating behavior of Cook Inlet beluga whales, Delphinapterus leucas, observed from an aircraft

“…However, these behaviors closely resemble the specifi c behavioral events of previously observed beluga whales courting and mating in captivity (Hill et al, 2015). The seasonality of these apparent courting and mating behaviors in CIBW correspond with reported spring mating seasons for the Arctic populations (Burns and Seaman 6 ) as well as captive belugas (Robeck et al, 2005).…”

“…Although mating and social behaviors have been described for captive beluga whales (Hill et al, 2015), it is logistically diffi cult to observe undisturbed behavior among free-ranging beluga. They inhabit remote, and in the case of the Cook Inlet beluga whale (CIBW), typically muddy waters.…”

Environmental changes and anthropogenic factors modulate social play in captive bottlenose dolphins (Tursiops truncatus)

“…For the analysis, only videos where at least 80% of the dolphins' bodies were visible were analyzed. A bout was considered as finished when the animals were conducting another behavior for at least 10 s or when one of the "players" stayed away for more than 10 s. When dolphins moved out of view (i.e., out of the recording area or in the indoor pools) while playing, the play bout was considered as ended except if they returned, still playing, within 10 s. The time they spent out of view was not recorded but the time before and after they left was recorded as SERRES AND DELFOUR (Hill et al, 2015;Holobinko & Waring, 2010;Janik, 2015;Miller et al, 2011;Tamaki, Morisaka, & Taki, 2006;Weinpress & Herzing, 2015) Environmental events such as noisy events (e.g., temporary construction work around the pool) and potential enrichments (e.g., man-made objects in the pool; California sea lions (Zalophus californianus) in the pool) were also investigated. These special events (e.g., construction work around the pools, California sea lions or free divers in the pool, and toys in the pool) were noted.…”

Diffusion tractography reveals pervasive asymmetry of cerebral white matter tracts in the bottlenose dolphin (Tursiops truncatus)

“…It would be of interest in future DTI investigations of T. truncatus and other cetaceans to compare the lateralization of this direct auditory pathway to that of the arcuate fasciculus. In addition to the proposed functional lateralization of social acoustic signals, arcuate asymmetry may also be relevant to accumulating reports of behavioral lateralization in delphinoids regarding visual (Karenina et al 2010 ; Thieltges et al 2011 ; Karenina et al 2013a , b ; Yeater et al 2014 ), somatosensory, and motor (Johnson and Moewe 1999 ; Sakai et al 2006 ; Hill et al 2015 ) social signaling.…”