Many creatures mate for life. People, who often bungle this commitment, are shamed by such devotion in the wild. Watching a pair of swans glide across the surface of a still pond, we are stirred to admiration, even reverence, knowing how far they surpass us in manner and form.
Swans are inarguably beautiful, as are various other animals that lead devoted lives: turtle doves, wolves, French angelfish, golden eagles. For these glorious beasts, the discipline of monogamy seems a fitting attribute, a sort of noblesse oblige.
But what of the shingleback skink? Tiliqua rugose: a bob-tailed, slow moving, blue-tongued lizard. Found only in Australia, this lowly beast is one of earth’s most faithful inhabitants. Every autumn, for up to twenty years, it will seek out the same mate, the male inevitably finding the female by her scent trail. During their initial courtship and upon their annual reunion, the male will lick and softly prod the female. For two months they stay together, the male closely following the female as she makes her way across the outback. If one is killed, the other will stay with the body for several days, giving it a gentle nudge now and then as if to encourage animation.
Tiliqua rugose goes by several common names: stump-tailed lizard, shingleback skink, sleepy lizard, pinecone lizard, two-headed lizard (because the fat truncated tail mimics the head, minus the eyes and mouth). The skin of this reptile is dark brown, sometimes with yellow spots, and the protruding scales resemble armor. The eye are small and reddish-brown; the tongue is a brilliant blue. Reaching eighteen inches in length, the shingleback skink weighs in at a whopping two pounds. During the day it travels across open country foraging for flowers, berries and succulent leaves, as well as the occasional snail and beetle, which it handily crushes with its powerful jaws. At night it sleeps in leaf litter or under logs or rocks.
Six months after the male locates his mate, the female gives birth to two or three young. This process takes much out of her as the progeny can exceed eight inches in length and weigh nearly half a pound—compare a woman giving birth to a three-year-old child. As soon as they emerge, the young skinks dispatch the placenta, then promptly head out, en route to their own chosen life mates.
So how does unstinting loyalty benefit the shingleback skink? Certainly any healthy female could produce viable young; variation might even strengthen the gene pool. But somehow this lowly lizard was bequeathed with devotion, the urge to seek its private treasure again and again, at any cost. Equally impressive are the researchers who brought us these facts, who braved the harsh Australian outback to study this odd creature day and night, year after year.