Novel foraging strategies observed in a growing leopard seal (Hydrurga leptonyx) population at Livingston Island, Antarctic Peninsula

Abstract

Background: Leopard seals are apex predators that can alter the community structure of Antarctic coastal ecosystems. Previous behavioral studies were limited to land-based, daytime observations of foraging leopard seals. Consequently, foraging tactics, social behaviors, and indirect ecosystem impacts are poorly understood. Here, we present the first analysis of animal-borne HD video footage for foraging leopard seals. Each CRITTERCAM was deployed with Fastloc GPS and time-depth recorder instruments providing fine-scale habitat context for observed foraging behavior. We analyzed seven deployments obtained in January and February of 2013 and 2014 from adult female leopard seals near mesopredator breeding colonies on Livingston Island, Antarctica. Results:The average deployment length was 4.80 ± 2.45 (range 0.86-9.12) days, which covered a total of 16 foraging trips. Habitat use, along with 39 prey capture attempts, and 11 leopard seal social encounters were scored from 50.3 h of video data. We obtained 3,833 post-filter GPS positions, accurate to within 70 m, and the mean dive depth was 14.84 ± 8.98 m. Leopard seal foraging focused on four prey items: Antarctic fur seals, Antarctic fur seal pups, pygoscelid penguins, and demersal notothen fishes. Ambush tactics used only by a subset of leopard seals drove high capture success rates of fur seal pups. We identified novel prey-specific foraging tactics including stalking and flushing notothen fishes.Conclusions: Leopard seals have been described as generalist apex predators; however, video and movement data suggest that leopard seals employ specialized prey-specific hunting tactics. Although preliminary, our findings indicate that leopard seals can affect coastal ecosystems through pathways beyond direct predation, including intraspecific kleptoparasitism and facultative scavenging/food caching. Our results suggest that position-integrated video data will be vital in quantifying the ecological impact of this abundant and versatile apex predator.

Prey capture and processing behaviors vary with prey size and shape in Australian and subantarctic fur seals

“…5K). This is similar to kleptoparasitism observed in wild leopard seals, where larger animals were found to steal prey items from smaller ones during aggressive agonistic interactions (Krause et al 2015). Figure 6.…”

Chew, shake, and tear: Prey processing in Australian sea lions (Neophoca cinerea)

“…Recently, a number of studies have looked at prey acquisition behavior in a range of species, showing them to use varying combinations of suction and biting to capture prey (Ydesen et al 2014;Marshall et al 2008Marshall et al , 2014Marshall et al , 2015Hocking et al 2013Hocking et al , 2014Hocking et al , 2016. Future study of wild pinnipeds (e.g., Bowen et al 2002, Krause et al 2015 will be able to extend on what has been learned from these captive studies by indicating the frequency at which different behavior are performed. But by looking beyond prey acquisition to the behaviors used to process prey that is too large to swallow whole, we hope that this study will provide fresh insights into the role of behavior in shaping prey choice in pinnipeds.…”

Calibrating the time span of longitudinal biomarkers in vertebrate tissues when fine‐scale growth records are unavailable

“…Typically, marine mammals consume small prey relative to their body size (Tucker and Rogers 2014). However, the leopard seal takes large-bodied, high-trophic prey, including crabeater, Weddell and southern elephant seals (Hall-Aspland and Rogers 2007), fur seals (krause et al 2015), and penguins (Rogers and Bryden 1995, Hall-Aspland and Rogers 2004, krause et al 2015. Leopard seals consume more large-bodied prey, using a raptorial "grip-and-tear" feeding style, than any other pinniped (Rogers 2009).…”

“…Leopard seals are believed to act as a "switching predator," targeting different prey based on seasonal availability (Rogers 2009). They switch from a largely krill-based diet in the winter (Lowry et al 1988(Lowry et al , kuhn et al 2006(Lowry et al , guerrero et al 2016) to a penguin and seal-based diet in the summer (Rogers and Bryden 1995, Hall-Aspland and Rogers 2004, krause et al 2015.…”