Allocare, investment in offspring from non-parents, poses an evolutionary enigma. While the fitness trade-offs driving parental care are universal, alloparents may be driven by kin selection, reciprocation, the need to acquire parenting skills (‘learning-to-parent’), an indiscriminate attraction towards infants (‘natal attraction’), or a combination of multiple drivers. Among belugas (Delphinapterus leucas), allocare has been reported in wild and captive populations, but its underlying mechanisms remain untested. Using over 1800 focal observations, we quantified alloparental associations in St. Lawrence Estuary (SLE) belugas to determine whether the learning-to-parent and natal attraction hypotheses are consistent with patterns of allocare in this population. We found that subadults showed little interest in providing allocare and that alloparental investment remained constant across offspring age classes. As the observed patterns of allocare are inconsistent with both the learning-to-parent and natal attraction hypotheses, allocare in SLE belugas is likely driven by kin selection, reciprocation, or a combination thereof.
Drones have become an important research tool for studies of cetaceans, providing valuable insights into their ecology and behavior. However, drones are also recognized as a potential source of disturbance to cetaceans, particularly when flown at low altitudes. In this study, we examined the impact of drones on endangered St. Lawrence belugas (Delphinapterus leucas), and reviewed drone studies of cetaceans to identify altitude thresholds linked to disturbance. We repurposed drone footage of free‐living belugas taken at various altitudes, speeds, and angles‐of‐approach, and noted the animals' reactions. Evasive reactions to the drone occurred during 4.3% (22/511) of focal group follows. Belugas were more likely to display sudden dives during low‐altitude flights, particularly flights below 23 m. Sudden dives were also more likely to occur in larger groups and were especially common when a drone first approached a group. We recommend that researchers maintain a lower altitude limit of 25 m in drone‐assisted studies of belugas and approach larger groups with caution. This recommendation is in line with our literature review, which indicates that drone flights above 30 m are unlikely to provoke disturbance among cetaceans.
Allocare, care for offspring from nonparents, can carry important benefits for offspring. We investigated the potential benefits of allocare to offspring by examining contexts associated with allocare among St. Lawrence belugas in Sainte-Marguerite Bay, a high-residency area, and the Saguenay Fjord, a transit area. We hypothesized that calves receive similar benefits from mothers and alloparents, namely, protection and energetic benefits, while juveniles associate with alloparents for social purposes. As such, we expected that calves would associate with mothers and alloparents more frequently when exposed to potential dangers, such as adult males and vessel traffic, and in energetically costly contexts, such as the flood tide and during travel, while juveniles would associate with alloparents more frequently during social behavior. We found no trends between allocare and any variables tested. However, we found that calf maternal care in the fjord decreased significantly during socialization, particularly calf-calf socialization.We also found that juvenile maternal care in the fjord decreased significantly when males were present, possibly because juveniles sought associations with males. These findings emphasize the importance of socialization for beluga offspring of all ages. Both maternal care and allocare persisted across contexts in Sainte-Marguerite Bay, highlighting its possible importance as an offspring-rearing ground.
From the perspective of prey, movement synchrony can represent either a potent anti-predator strategy or a dangerous liability. Prey must balance the costs and benefits of using conspecifics to mediate risk and the emergent patterns of risk-driven sociality depends on the spatial variation and trait composition of the system. Our literature review outlined the prevailing, but not universal, trend of animals using sociality as an antipredator strategy. Empirically, we then used movement synchrony as a measure of social antipredator response of two ungulates to spatial variation in predator and prey habitat domains. We demonstrated that these responses vary based on prey vulnerability and predator hunting modes. Prey favored asynchrony when calves were present and within habitat domains of ambush predators but not pursuit predators. By unifying community ecology concepts such as habitat domains with movement ecology we provided a comprehensive evaluation of factors mediating prey social response to predation risk.
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