Skinks have also contributed greatly to the understanding of reptile reproduction. Although most skink species deposit their eggs in nests and then abandon them, many are live-bearers (viviparous).
Skinks are more slender than geckos, with narrow heads and small eyes, a narrow neck which is nearly as wide as the head, and smooth, shiny scales on the surface of the skin. There are 78 species of skink in New Zealand but new species are still being discovered.
Among the live-bearing species are some that have developed a complex placenta for transferring nutrients directly to the developing offspring. In one skink, the South American species M. heathi, the placenta is as developed and complex as that found in mammals.
Like frogs, they travel through life alone, getting together only when it’s time to mate in May and June. The female lays up to a dozen eggs in a nest she makes under rocks or logs. But that’s as maternal as she gets! When the little skinks hatch about a month later, they’re on their own to forage for food and avoid predators. Skinks start off life with a bright metallic blue tail and dark body with five light-coloured stripes that run from their snout to their tail. As they age, their tail and body fades to a more uniform brown-grey. They grow to about 20 cm in length.