By counting the number of endangered panthers hit and killed by cars in Florida, researchers have estimated the population size of this rare cat. They say that it is the first statistically robust population estimate for the animals across their breeding range.

Brett McClintock of the National Marine Mammal Laboratory in Seattle, Washington, and his team used data on reported collisions with Puma concolor coryi (fewer than 20 per year) and traffic densities, as well as information from a small number of radio-collared panthers to estimate the total population across the state. They show that panther numbers seem to be slowly increasing, but may never have exceeded 150 individuals between 2000 and 2012.

This method could be applicable to other rare animals, the researchers say.

J. Appl. Ecol. http://doi.org/5sg (2015)