Natural Exterminator: Blue Tail Skink
Tara A. Spears
Talk about checks and balances! One of nature’s ways of keeping the spider and insect populations from over-dominating is the spiffy looking Five lined blue tail skink, eumeces fasciatus. This unique looking little lizard dines on ants, spiders, beetles, roaches, worms, millipedes, and other annoying insects so it is a great critter to have in your garden.
The Five-lined Skink is a common warm weather lizard. They grow up to eight inches long, with males growing slightly larger than females. This young reptile is usually black or dark brown, with five light stripes down their backs with a brilliant blue tail. Stripes and tail fade as the skink matures, so the adult skink may look all brown. The markings vary somewhat due to geographic location.
Five-lined skinks are fairly sedentary animals, living within a small area for most of their lives. The home range of the skink includes locations for basking, hiding, feeding, and nesting. These home ranges can overlap, and often many skinks may share something like a pile of rocks on which to bask. Five-lined skinks are also territorial animals however, particularly during breeding season. Male skinks will claim territories several yards in diameter, and take responsibility to both protect that territory and attract mates in the territory to breed.
In examining another skink, various visual displays, aggressive actions and tongue-flicking behaviors may be employed. For example, a male may “rub his chin on the substrate and then rush at another lizard with his mouth wide open,” said reptile expert Tyning. The invading other lizard can either return the behavior, meaning a fight over the territory ensues, or it can run away and leave the aggressor’s territory. In the case of a fleeing skink, the defender often will chase the other individual for a few feet before returning to his territory.
Courtship and Mating
Male adult Five-lined Skinks often have bright orange jaws during the breeding season, which in Jaltemba Bay is generally late winter, February and March. Five-lined skinks don’t engage in extensive courtship procedures. When the male approaches a female, she either retreats and leaves the male’s territory, or remains and allows him to continue courting her. If the female is receptive, the female points her snout down to the ground and the male grasps her neck in his jaws. He wraps his tail around hers and either he lifts her tail or she lifts it of her own accord. Copulation occurs in this position, lasting up to ten minutes after which the female leaves the male’s territory.
Unlike most other skinks, those of the genus Eumeces exhibit egg-laying behavior. About a month after mating, the female five-lined skink builds her nest and deposits her eggs. Normal egg-laying sites include in rotting logs and stumps, beneath rocks and boards, in the litter covering the forest floor, and in moist soil. The nest is formed when the female scrapes away debris with her feet, or when a female enlarges an indentation in the substrate with enlarged movements of her body. Up to eighteen eggs can be deposited at once, and the female takes a protective position curled up around them. This egg-brooding behavior is exhibited in only a few other genesis of lizards. What is even more amazing for a cold blooded lizard, the Five-lined Skink mother periodically rolls each of her eggs. Sometimes the female also eats some of her eggs! But once the babies hatch, the female pays no more attention to them.
Young skinks have very clear stripes and a bright blue tail. Females may keep a very full bluish-gray tail as they age, but males’ tails will turn brown. The tail serves as a last resort protection device for the skink against predators. Normally very easily frightened when approached, the five-lined skink relies on little other than its speed to escape prey. In case of capture however, the skink readily loses a large part of its tail when grasped.
More so than in other types of lizards, the skink’s lost tail thrashes violently about for many minutes (L.J. Vitt). The idea behind this defense tactic is to confuse the predator and attract its attention enough to allow the captured skink to escape and scurry away. The bright blue coloration of the juvenile tail may function to enhance the attractiveness of the tail. In addition, the length of the tail being similar to that of the body directs the predator even more to attack the non-vital tail instead of the individual. Because of the arrangement of vertebrae, muscles and blood vessels in the tail, healing is instantaneous and little blood is lost before the wound is healed and a new tail begun growing. This characteristic of the skink’s tail makes it a very efficient defense mechanism for the animal.
Enjoy having the hardworking Five-lined Skink in your yard: it’s a great organic way to control the pesky tropic insects. It is very shy, so you’re more likely to see one if you are sitting with a cocktail/beer and enjoying the fantastic weather.