Activity and social interactions in a wide-ranging specialist scavenger, the Tasmanian devil (Sarcophilus harrisii), revealed by animal-borne video collars

Abstract

Observing animals directly in the field provides the most accurate understanding of animal behaviour and resource selection. However, making prolonged observation of undisturbed animals is difficult or impossible for many species. To overcome this problem for the Tasmanian devil (Sarcophilus harrisii), a cryptic and nocturnal carnivore, we developed animalborne video collars to investigate activity patterns, foraging behaviour and social interactions. We collected 173 hours of footage from 13 individual devils between 2013 and 2017. Devils were active mostly at night, and resting was the most common behaviour in all diel periods. Devils spent more time scavenging than hunting and exhibited opportunistic and flexible foraging behaviours. Scavenging occurred mostly in natural vegetation but also in anthropogenic vegetation and linear features (roads and fence lines). Scavenging frequency was inversely incremental with size e.g. small carcasses were scavenged most frequently. Agonistic interactions with conspecifics occurred most often when devils were traveling but also occurred over carcasses or dens. Interactions generally involved vocalisations and brief chases without physical contact. Our results highlight the importance of devils as a scavenger in the Tasmanian ecosystem, not just of large carcasses for which devils are well known but in cleaning up small items of carrion in the bush. Our results also show the complex nature of intraspecific interactions, revealing greater detail on the context in which interactions occur. In addition, this study demonstrates the benefits of using animal-borne imaging in quantifying behaviour of elusive, nocturnal carnivores not previously seen using conventional field methods.

Space use and temporal partitioning of sympatric Tasmanian devils and spotted‐tailed quolls

“…Spatial segregation at the home range level did not occur between devils and quolls, nor did we observe strong fine-scale patterns of avoidance in core area placement. In a different study that radio-tracked devils and quolls to their dens during the day, we found a quoll's maternal den only 400m away from a devil's maternal den (Andersen et al 2020). This further supports that there is little core area segregation between the two species.…”

“…Therefore, the differences in temporal activity and movement patterns could be attributed to the different foraging strategies of devils and quolls. Devils are pounce‐pursuit predators (Jones 2003) that hunt using a moving search (Pemberton 1990) but scavenge more than they hunt at our study site (Andersen et al 2020). Their foraging strategy may be to cover sufficient distance in a night to find food and then return to a den.…”

“…Devils and quolls were trapped in PVC pipe traps (diameter 315 mm × length 875 mm), baited with meat from local prey species (Bennett’s wallaby and pademelon). As devils and quolls move along roads (Andersen et al 2017b), traps were placed more than five metres from the side of a road or a dirt/gravel vehicle track and were checked for captures at dawn. Upon capture, animals were transferred to a hessian sack without anaesthesia and were weighed, sexed and microchipped for future identification.…”

A Comprehensive Overview of Technologies for Species and Habitat Monitoring and Conservation

“…Thanks to camera miniaturization, animal-borne videography can obtain information about the ecology (diet, habitat use) and behavior (mate selection, threat avoidance) that could be critical for conservation. For example, video loggers have been deployed to study ecology and behavior—for example, on crows (Rutz and Troscianko 2013 ) and Tasmanian devils (Andersen et al 2020 ). So-called AVEDs (animal-borne video and environmental data collection systems) integrate environmental sensors (e.g., audio, location, temperature, acceleration).…”

The Macroscopic and Radiographic Skull and Dental Pathology of the Tasmanian Devil (Sarcophilus harrisii)

“…While its range historically extended throughout continental Australia, it is now only found in the wild inhabiting the island state of Tasmania, located south of mainland Australia across the Bass Strait ( 1 , 3 , 4 ). Weighing ~8–10 kilograms for males and 6–7 kilograms for females, the Tasmanian devil is a pounce-pursuit predator, forager, and facultative scavenger ( 1 , 5 , 6 ). While younger devils favor a diet of smaller mammals, birds, amphibians, reptiles, and insects, as individuals age their diet shifts to primarily macropods such as Red-necked wallabies ( Notamacropus rufogriseus ) and Rufous-bellied pademelons ( Thylogale billardierii ), both as carrion and live prey ( 1 , 2 , 4 , 5 ).…”