The common five-lined skink hibernates during the colder winter months between October and April or May, usually in tree stumps, logs, rock crevices or piles of vegetation (3). During the warmer months, it basks on logs or on the ground to raise its body temperature to between 28 and 34 degrees Celsius, which enables it to become active (3). During colder days, this species remains inactive, hidden under logs, rocks or piles of bark (2). In Georgia, juvenile common five-lined skinks are active throughout the warmer months, while activity among adults of the species appears to be concentrated during the month of May (2). The common five-lined skink feeds on a variety of small invertebrates (2) (3). Large males with strong jaws may eat young lizards or mice (3). Captive common five-lined skinks have been observed eating berries (3).
The common five-lined skink breeds in the spring (2). During this time, the male defends its territory against other males, but allows the presence of females and juveniles (3). Males have been observed attacking each other using their powerful jaws (3). When ready to mate, the male common five-lined skink approaches the female from the side and bites her neck in order to enable copulation (3). The female lays between 4 and 18 eggs about a month later, usually inside a rotten log or tree stump (2) (3). The eggs are around 13 millimetres in length and are very thin shelled (3). The female common five-lined skink leaves the nest to bask and sometimes to feed, but otherwise remains with its eggs, curling its body around them, turning them with its snout and viciously defending them against intruders (3). The female remains with its eggs until they hatch, urinating on them to keep them moist, and eating any that spoil before they hatch (3).
The common five-lined skink is skittish by nature and will flee threatening intruders (2). If captured, it will readily bite, but it is unable to break human skin (2). A male common five-lined skink can defend itself against attack by biting the predator with its strong jaws (3).
The common five-lined skink is predated by several species of snake, moles, opossums, skunks, cats and hawks, although the most significant predator is thought to be the short-tailed shrew (Blarina brevicauda) (3).
The tail of the common five-lined skink is able to autotomise spontaneously (4). This is when the tail breaks off and twitches for several minutes with the aim of distracting the attacker and allowing the skink to escape (4). Experiments involving natural predators of the common five-lined skink have shown that the skink holds its tail off the ground to detract attention away from the body. Once the predator is able to gain a secure hold of the tail, a powerful muscle contraction results in tail autotomy. Following this, there is very little bleeding or fluid loss from the tail (6). The detached tail twitches on the ground. If the tail is not eaten by the attacker, the twitching may result in it being buried into leaf litter or loose surface soil (2). If the skink survives the attack, it may return later to find the tail using chemical cues, and eat it (2). A new tail quickly grows from the stump of the old one, and it is thought that the negative effects of losing the tail are offset by the increased chance of escaping predators (3). However, as the skink matures, the cost/benefit ratio for the process of tail autotomy changes. Tails, and the energy reserves associated with them, are important for reproduction or reproduction-related activity. This is the reason that the tails of adult common five-lined skinks are more cryptically coloured, and that the conspicuous blue colouration is only seen in juveniles (6).