What If Gone

Species → Tasmanian Devil

Tasmanian Devil

Sarcophilus harrisii

10,000 wild individuals, approximate estimate
Extinction risk Endangered
Apex predatorScientific controversyMesopredator releaseCatastrophic decline
Tasmanian Devil (Sarcophilus harrisii)
Photo: JJ Harrison, Wikimedia Commons (CC BY-SA 3.0)

What if it disappeared?

Impact Moderate
In Tasmania

In regions where devil facial tumour disease has raged the longest, feral cat occurrence increases and is significantly negatively associated with devil occurrence; the smallest of the native mesopredators, the eastern quoll, is declining rapidly there — consistent with protection it once drew from devils suppressing mid-sized predators.

Documented
Detail

Hollings, T., Jones, M., Mooney, N. & McCallum, H. (2014). Trophic Cascades Following the Disease-Induced Decline of an Apex Predator, the Tasmanian Devil. Conservation Biology, 28(1), 63–75.

The study draws on spotlighting count data conducted across Tasmania over several decades, both before and after the disease's arrival in each region. Devil decline is immediate in every affected region, with no sign of recovery, and coincides with the rise in feral cat occurrence.

Re-examination, Tasmania

A study focused specifically on quolls and cats does not find a clear increase in cat abundance following devil decline, and proposes a different explanation: cats may be hindering the recovery of already-weakened quolls, without having caused their initial decline.

Insufficient
Detail

Fancourt, B.A., Hawkins, C.E., Cameron, E.Z., Jones, M.E. & Nicol, S.C. (2015). Devil declines and catastrophic cascades: Is mesopredator release of feral cats inhibiting recovery of the eastern quoll? PLoS ONE, 10(3), e0119303. The authors find no difference in the relative abundance of quolls, cats, or devils between regions based on how long the disease has been present; they observe only a change in cat behavior (increased nocturnal activity, less temporal avoidance of other predators) where devils have declined the longest, and propose a 'predator trap' hypothesis limiting recovery rather than a classic mesopredator release. They themselves note the absence of pre-disease baseline data, which limits any firm causal conclusion.

Documentation

Last verified: August 14, 2026