Populations of the same species often face different selection pressures and, increasingly, the demography of populations
within a species has been shown to be highly variable. Knowledge of such intraspecific differences has implications for
substituting demographic data, a practice that is often necessary for population modelling due to missing parameters.
The red fox Vulpes vulpes, a widely-studied, widespread and economically important species, offers an opportunity to
consider the degree of intraspecific variability in the demography of a carnivore and to test the consequences of interpopulation
data substitution. We use published life history data to review the extent and quality of demographic data
for fox populations. Using demographic descriptors, matrix models, and perturbation analyses, we identify important
demographic properties and classify interpopulation variation along the fast–slow continuum. We also illustrate the
consequences of data substitution in demographic models. Data quality varies substantially between reviewed studies.
Sufficient data exist to model the demography of eight of 56 study populations. Modelled populations have a tendency
towards positive population growth, with survival and fecundity of the youngest age class contributing most to
that growth. Metrics point to strategies ranging from medium to fast life histories. While broad demographic similarities
exist among fox populations, our results imply considerable demographic variation between populations. We
show that significant differences in model outcomes based on substituted data are dependent on the parameter replaced,
and that geographic proximity does not imply demographic similarity. Superficially, the red fox appears to have been
well studied, yet there are remarkably few usable demographic data from much of its range. Despite 70 years of published
studies, we were unable to examine the effects on demographic parameters of harvesting regimes, density and weather.
We propose improvements to enhance the value of demographic data, both for foxes and for other species.