Ontogeny of antipredator behaviour in striped skunks (Mephitis mephitis)

The defensive display of a threatened adult striped skunk (Mephitis mephitis) involves visual, auditory, and olfactory signals. Detection of a potential predator leads to either avoidance (run, hide, or den) or confrontational (tail-up, stomp, hiss, scratch, charge, aim, and spray) behaviours. Seventy skunks born in captivity were handled at five-day intervals starting at seven days of age and up to 52 days of age. The development of defensive behaviours (tail-up, stomp, run, aim, hide, spray, hiss, scratch, charge, and bite) and physical attributes (eye opening, external auditory meatus opening, and teeth eruption) were recorded. Tail-up, which signifies alertness and enhances warning colouration, was the most common and earliest defence behaviour observed. Musk was present at seven days of age, though the ability of a skunk to forcefully expel its chemical defence is not developed until 17 days. Initially spray events are not aimed at the threat; directed spray is initiated following eye opening at 32 days. Unlike adult striped skunks, juveniles will spray early on in the warning display, and spray behaviour is developed prior to behaviours that require greater mobility (aim, run, hide, scratch, and charge) or direct contact (bite). The proportion of individuals attempting avoidance behaviours, such as run and hide, increased as the skunks matured. However, the tail-up and spray behaviours were more frequent at 32 days of age than at 52 days of age. Inversely, the run and hide behaviour occurred more often at 52 days of age than at 32 days. Chemical defence in striped skunks may be more vital to the survival of juvenile skunks than adults that are capable of displaying the entire range of anti-predator behaviours, have greater experience, and potentially fewer predators.