Our interpretation of animal social structures is inherently dependent on our ability to define association criteria that are biologically meaningful. However, association thresholds are often based upon generalized preconceptions of a species’ social behaviour, and the impact of using these arbitrary definitions has been largely overlooked. In this study we suggest a probability-based method for defining association threshold...

Data collected opportunistically aboard marine wildlife tourism vessels are an inexpensive source of spatial information on the target species. Although these data are often challenging to analyze, they can be used to monitor spatiotemporal changes in species distribution and behavior. Disruptions from whale‐watching vessels to behaviors such as foraging can be particularly harmful to cetaceans, but impacts could be reduced if...

Photo-identification methods depend on markings that are stable over time. Using a large dataset of photographs taken over a 31-year period, we evaluate the reliability, rate of change and demographic trends in different mark types on northern bottlenose whales ( Hyperoodon ampullatus ) in the Endangered Scotian Shelf population, and assess the prevalence and severity of anthropogenically caused markings. Only fin notches and...

Alloparental care happens when a calf is cared for by an adult that is not their parent. Although alloparental care is common in social mammals, its prevalence is difficult to assess in cetaceans, and has not been studied in Globicephala melas . A population off Cape Breton, Nova Scotia, has been studied from whale‐watching vessels since 1998, during July and August each year. From 2009 to 2011, we collected photo identificati...

When animals live in cohesive groups they need to make consensus decisions about movements. As a very large‐scale example of communal movement, nomadic female sperm whales ( Physeter macrocephalus ) travel about 50 km per day as coherent groups of 10–50 animals spread over several km of ocean. From 543 h of data during which 3,873 headings of small clusters of whales or individual whales were recorded, I quantified the heading...

When individuals primarily associate with and learn from those who behave similarly, society and culture become closely tied. Sperm whales ( Physeter macrocephalus ) exhibit multilevel social structure, the levels of which are differentiated in part by characteristic cultural behaviors. Sperm whales are organized into sympatric clans, with distinctive vocal repertoires that are socially learned. Other behaviors, such as moveme...

There is substantial geographic variation in the behavior and social structure of sperm whales worldwide. The population in the Eastern Caribbean is thought to be isolated from other areas in the North Atlantic. We describe the behavior and social structure of the sperm whales identified off Dominica during an eight year study (2005–2012; 92% of photographic identifications) with supplementary data collected from seven other o...

Living in groups is usually driven by predation and competition for resources. River dolphins do not have natural predators but inhabit dynamic systems with predictable seasonal shifts. These ecological features may provide some insight into the forces driving group formation and help us to answer questions such as why river dolphins have some of the smallest group sizes of cetaceans, and why group sizes vary with time and pla...

This study is part of an on‐going effort to evaluate and monitor river dolphin populations in South America. It comprises the largest initiative to estimate population size and densities of Inia and Sotalia dolphins using statistically robust and standardized methods. From May 2006 to August 2007, seven visual surveys were conducted in selected large rivers of Bolivia, Colombia, Brazil, Ecuador, Peru, and Venezuela in the Amaz...

The vocal repertoires of group‐living animals may communicate individual or group identity. Female and juvenile sperm whales live in long‐term social units that can be assigned to vocal clans based on the pattern of clicks in coda vocalizations. An unusual set of circumstances allowed us to record the vocalizations of photo‐identified individuals within a single social unit over a 41 d period. Using click interpulse intervals,...