Camouflage or Coincidence? Investigating the Effects of Spatial and
Temporal Environmental Features on Feral Cat Morphology in Tasmania
Abstract
Variations in coat morphology are well-documented among felids and are
theorised to aid in camouflage during stalk and ambush hunting. A
diverse array of coat types has arisen in Felis silvestris catus (feral
cats) through domestication and subsequent selective breeding. This
species has successfully spread across Australia over the past 200
years, raising the question of whether any specific coat types offer an
adaptive advantage. We used 24 657 camera-trap images of feral cats in
Tasmania, Australia, and assigned each cat observation a coat colour and
pattern. We analysed these data to examine how different spatial
features affect the presence or absence of coat types. We also tested if
cats with differing coat types were active on different days in response
to temporal features, including moon luminosity (full or new). Elevation
was positively associated with the presence of orange (odds ratio= 1.74,
97.5% confidence interval= 1.25, 2.4) and tortoiseshell (odds ratio=
1.93, CI= 1.32, 2.83) cats, while blotched brown cats were negatively
associated with elevation (odds ratio= 0.74, CI= 0.59, 0.93), relative
to black cats. All coat types were 1.2 to 2 times more likely to be
active on nights with a new moon, except for orange cats who were
equally active regardless of moon luminosity (odds ratio= 0.94, CI=
0.62, 1.42). Our results indicate that coat types are equally successful
across Tasmania, perhaps owing to naïve prey or limited predator
competition. The high activity of orange cats irrespective of moon phase
may be reflective of the male cat’s tendency to patrol territory, as
opposed to favouring dark nights for hunting. Future studies should
consider comparing the coat types found in feral cats to adjacent
domestic populations, and against a wider array of habitat types to
further investigate the potential for selective pressure on feral cat
coat types in Australia.