Jaguars (Panthera onca) increase kill utilization rates and share prey in response to seasonal fluctuations in nesting green turtle (Chelonia mydas mydas) abundance in Tortuguero National Park, Costa Rica

Sustained use of marine subsidies promotes niche expansion in a wild felid

The use of marine subsidies by terrestrial predators can facilitate substantial transfer of nutrients between marine and terrestrial ecosystems. Marine resource subsidies may have profound effects on predator ecology, influencing population and niche dynamics. Expanding niches of top consumers can impact ecosystem resilience and interspecific interactions, affecting predator-prey dynamics and competition. We investigate the occurrence, importance, and impact of marine resources on trophic ecology and niche dynamics in a highly generalist predator, the caracal (Caracal caracal), on the Cape Peninsula, South Africa. Caracals have flexible diets, feeding across a wide range of terrestrial and aquatic prey. We use carbon and nitrogen stable isotope analysis of fur samples (n = 75) to understand trophic position and niche shifts in coastal and inland foragers, as well as the implications of a diet rich in marine resources. We found significant differences in isotope signatures between these groups, with higher δ13C (P < 0.05) and δ15N values (P < 0.01) in coastal foragers. Isotope mixing models reveal that these elevated signatures were due to non-terrestrial food subsidies, where approximately a third of coastal foraging caracal diet comprised marine prey. The addition of marine prey species to diet increased both the trophic level and isotope niche size of coastal foraging caracals, with potential impacts on prey populations and competition. Our results suggest that marine prey are an important dietary resource for coastal foraging caracals, where seabirds, including two endangered species, are a major component of their diet. However, there are likely risks associated with these resource benefits, as routine consumption of seabirds is linked with higher pollutant burdens, particularly metals. Increased encounters between this terrestrial predator and seabirds may be a result of increased mainland colonies due to changes in habitat availability and the highly opportunistic and generalist foraging behaviour of a native predator.

A review of environmental and anthropogenic variables used to model jaguar occurrence

Jaguars (Panthera onca) are a landscape species of conservation importance and our understanding of environmental and anthropogenic drivers of jaguar occurrence is necessary to improve conservation strategies. We reviewed available literature to simply describe environmental and anthropogenic variables used and found to be significant in occurrence modeling. We reviewed 95 documents published from 1980 to 2021 that focused on jaguar occurrence and that used 39 variable types (21 anthropogenic, 18 environmental) among different techniques, scales, and approaches. In general, these variables included both anthropogenic (roads, land use, human activities, and population) and environmental (climate, vegetation, ecological interactions, topographic, water, and others) factors. Twelve variables were identified as affecting jaguar occurrence overall, eleven at local scale and seven at broad scales (regional and continental). Focusing more specifically on the variables that correlate with occurrence should help researchers to make better predictions in areas without quantitative jaguar data.

Collaborative behaviour and coalitions in male jaguars (Panthera onca)—evidence and comparison with other felids

Abstract

Most large felids are classified as solitary species, with only lions (Panthera leo) and cheetahs (Acinonyx jubatus) exhibiting social, collaborative behaviours. Herein, we present evidence of the formation of male coalitions by jaguars (Panthera onca), based on data from five studies conducted with camera trapping, GPS telemetry, and direct observations in the Venezuelan Llanos and Brazilian Pantanal. Out of 7062 male records obtained with camera traps or visual observations, we detected 105 cases of male-male interactions, of which we classified 18 as aggression, nine as tolerance, 70 as cooperation/coalition, and eight as unidentified. In two studies, two male jaguars formed stable coalitions lasting over 7 years each. In the Llanos, each coalition male paired and mated with several females. For male jaguar coalitions, we documented similar behaviours as recorded earlier in lions or cheetahs, which included patrolling and marking territory together, invading territories of other males, collaborative chasing and killing other jaguars, and sharing prey. However, different from lions or cheetahs, associated male jaguars spent less time together, did not cooperate with females, and did not hunt cooperatively together. Our analysis of literature suggested that male jaguar coalitions were more likely to form when females had small home range size, a proxy of females’ concentration, while in lions, the male group size was directly correlated with the female group size. Similarly, locally concentrated access to females may drive formation of male coalitions in cheetahs. We conclude that high biomass and aggregation of prey are likely drivers of sociality in felids.

Significance statement

The division into social and solitary species in large felids has so far seemed unambiguous, with only lions and cheetahs classified as social species, in which male coalitions also occurred. Our data show that, under certain conditions, male coalitions may also form in jaguar populations. Factors that drive formation of male coalitions in lions and cheetahs, but not in other species of large cats, have not been clear until now. Our analyses indicate that in jaguars, lions, and cheetahs, the concentration of females likely plays the most important role. In jaguars, the probability of male coalition occurrence is highest in populations with the smallest mean female home range size (and thus likely high local density of females), while in lions, male group size is most strongly correlated with female group size.

Threats and Vulnerabilities for the Globally Distributed Olive Ridley (Lepidochelys olivacea) Sea Turtle: A Historical and Current Status Evaluation

The olive ridley (Lepidochelys olivacea) is the most abundant of all seven sea turtles, found across the tropical regions of the Atlantic, Pacific, and Indian Oceans in over 80 different countries all around the globe. Despite being the most common and widely distributed sea turtle, olive ridley populations have been declining substantially for decades. Worldwide, olive ridleys have experienced a 30–50% decline, putting their populations at risk and being considered an Endangered Species by the IUCN. Natural habitat degradation, pollution, bycatch, climate change, predation by humans and animals, infectious diseases and illegal trade are the most notorious threats to explain olive ridley populations rapidly decline. The present review assesses the numerous dangers that the olive ridley turtle has historically faced and currently faces. To preserve olive ridleys, stronger conservation initiatives and strategies must continue to be undertaken. Policies and law enforcement for the protection of natural environments and reduction in the effects of climate change should be implemented worldwide to protect this turtle species.

Torn limb from limb: the ethology of prey-processing in Tasmanian devils (Sarcophilus harrisii)

The success of carnivorous mammals is determined not only by their ability to locate and kill prey, but also their efficiency at consuming it. Breaking large prey into small pieces is challenging due to the strong and tough materials that make up a carcass (e.g. hide, muscle, and bone). Carnivores therefore require a diverse suite of prey-processing behaviours to utilise their catch. Tasmanian devils are Australia’s only large marsupial scavengers and have the ability to consume almost all of a carcass. To determine how they do this we analysed 5.5 hours of footage from 21 captive and wild devils feeding at carcasses. We documented 6320 bouts of 12 distinct prey-processing behaviours, performed at frequencies that varied throughout feeds and between groups. The time point in the feed influenced the types of behaviours used. This is likely due to changing prey size, as different techniques appear better suited to handling whole carcasses or large pieces (pulling and pinning) or smaller pieces (holding and manipulating). Group size impacted the frequency of social pulling behaviours, which increased with the number of animals. Our findings highlight the range of prey-processing behaviours performed by scavenging devils when handling, breaking down, and consuming a carcass. The devils’ repertoire shares similarities with large carnivores that handle and consume whole carcasses as well as small carnivores that are adept in grasping and handling smaller prey.

Male residency of Sunda Clouded Leopard Neofelis diardi (Cuvier, 1823) (Mammalia: Carnivora: Felidae) in a peat swamp forest, Indonesian Borneo

The Sunda Clouded Leopard Neofelis diardi is the apex predator on the island of Borneo, yet little is known of its ecology.  We document the length of residency of male Sunda Clouded Leopards in Central Kalimantan, Indonesian Borneo.  Over 10 years, camera trap data have been obtained in the Sebangau peat swamp forest in a study area of ~ 105km2.  We identified 11 individuals (eight males, one female, and two with unknown sex), from 152 notionally independent photographs.  On average, males remained in the study area for 39.3 months (SE 8.3), or 3.3 years (SE 0.7), ranging from less than a month of residency up to 71 months.  Females were infrequently recorded, possibly as a result of human disturbance and/or high male densities.  Our results reveal that even a 10-year dataset is inadequate to answer some basic ecological questions, emphasising the importance of long-term monitoring of this species.

Adaptive social strategies in a solitary carnivore

Cost-benefit trade-offs for individuals participating in social behaviors are the basis for current theories on the evolution of social behaviors and societies. However, research on social strategies has largely ignored solitary animals, in which we assume that rare interactions are explained by courtship or territoriality or, in special circumstances, resource distributions or kinship. We used directed network analysis of conspecific tolerance at food sources to provide evidence that a solitary carnivore, the puma (Puma concolor), exhibited adaptive social strategies similar to more social animals. Every puma in our analysis participated in the network, which featured densely connected communities delineated by territorial males. Territorial males also structured social interactions among pumas. Contrary to expectations, conspecific tolerance was best characterized by direct reciprocity, establishing a fitness benefit to individuals that participated in social behaviors. However, reciprocity operated on a longer time scale than in gregarious species. Tolerance was also explained by hierarchical reciprocity, which we defined as network triangles in which one puma (generally male) received tolerance from two others (generally females) that also tolerated each other. Hierarchical reciprocity suggested that males might be cheating females; nevertheless, we suspect that males and females used different fitness currencies. For example, females may have benefited from tolerating males through the maintenance of social niches that support breeding opportunities. Our work contributes evidence of adaptive social strategies in a solitary carnivore and support for the applicability of theories of social behavior across taxa, including solitary species in which they are rarely tested.

Social interactions in a solitary carnivore

In total, 177 of 245 terrestrial carnivores are described as solitary, and much of carnivore ecology is built on the assumptions that interactions between adult solitary carnivores are rare. We employed Global Positioning System (GPS) technology and motion-triggered cameras to test predictions of land-tenure territoriality and the resource dispersion hypothesis in a territorial carnivore, the puma Puma concolor. We documented 89 independent GPS interactions, 60% of which occurred at puma kills (n = 53), 59 camera interactions, 11 (17%) of which captured courtship behaviors, and 5 other interactions (1 F-F, 3 M-F, and 1 M-M). Mean minimum weekly contact rates were 5.5 times higher in winter, the season when elk Cervus elaphus were aggregated at lower elevations and during which puma courtship primarily occurred. In winter, contacts rates were 0.6 ± 0.3 (standard deviation (SD)) interactions/week vs. 0.1 ± 0.1 (SD) interactions/week during summer. The preponderance of interactions at food sources supported the resource dispersion hypothesis, which predicts that resource fluxes can explain temporary social behaviors that do not result in any apparent benefits for the individuals involved. Conspecific tolerance is logical when a prey is so large that the predator that killed it cannot consume it entirely, and thus, the costs of tolerating a conspecific sharing the kill are less than the potential costs associated with defending it and being injured. Puma aggregations at kills numbered as high as 9, emphasizing the need for future research on what explains tolerance among solitary carnivores.

Depredación en la tortuga carey Eretmochelys imbricata por el Jaguar Panthera onca en la costa del Pacífico de Costa Rica

In the sea, the most common predators of adult sea turtles are sharks (i.e., Carcharhinus leucas, Carcharodon carcharias, Galeocerdo cuvier) (Witzell 1987, Cliff & Dudley 1991, Fergusson et al. 2000) and killer whales (Orcinus orca) (Fertl & Fulling 2007); while on their nesting beaches, female turtles are susceptible to predators like jaguars (Panthera onca) and crocodiles (Crocodylus acutus) (Ortiz et al. 1997, Heithaus et al. 2008).

First field observation of the predation by Jaguar (Panthera onca) on Olive Ridley sea turtle (Lepidochelys olivacea) at Nancite Beach, Santa Rosa National Park, Costa Rica

Jaguars have been recorded preying on adult female sea turtles on their nesting beaches in Costa Rica, Guyana, Mexico and Suriname (Fretey 1977, Autar 1994, Cuevas et al. 2014, Guildera et al. 2015). Jaguars prey on Green (Chelonia mydas), Olive Ridley (Lepidochelys olivacea), Hawksbill (Eretmochelys imbricata), and Leatherback (Dermochelys coriacea) sea turtles (see Fretey 1977, Autar 1994, Carrillo et al. 1994, Chinchilla 1997, Tröeng 2000, Heithaus et al. 2008, Veríssimo et al. 2012, Arroyo-Arce et al. 2014, Cuevas et al. 2014, Arroyo-Arce & Salom-Pérez 2015, Guildera et al. 2015). The capture effort and risk of injury associated with the predation of nesting sea turtles is expected to be lower relative to other prey species in the jaguar’s diet (Cavalcanti & Gese 2010). Additionally, they can be key resources when other pr ey availability is low (Veríssimo et al. 2012).