The Mighty Modifications of the Yellow-Spotted Goanna

A photo of a yellow-spotted goanna. Its a sleek yellow and brown lizard who's sticking out its pink and blue tongue.
Photograph by Dr. Caesar Sengupta

It’s a natural instinct to shelter our young underground, but the yellow-spotted goanna (Varanus panoptes) does this with remarkable determination and style. Not only is her burrow a unique helical shape, a spiral descending staircase, but it is also deep—unspeakably deep for a reptile crèche—at a dozen feet down. It takes an expectant mother more than a week to excavate her artful burrow, during which time she remains fully buried, at risk of suffocation if not for a small pocket of breathing room kept open by her corkscrewing motion. But the extraordinary effort is worth it. The eggs require a luxurious eight months to incubate, a would-be death sentence in a shallower nest during the ferociously hot, dry season of northern Australia, but this far down, the dirt is cool and damp, a perfect nursery.

By burrowing close together, yellow-spotted goannas create communal warrens that may hold hundreds of their vulnerable young. And over time, as the offspring leave and the burrows collapse, they open enticing nooks for a variety of sheltering frogs, reptiles, and insects. They are ecosystem engineers who, like dam-building beavers and reef-shaping coral, actively modify their surrounding environments, providing safety for others. In the face of harrowing circumstances, escalating threats, and expanding uncertainties, these parents look to the earth to protect their children.

Like all good citizens, they give back.

Kathleen Yale is Orion‘s digital editor and the author of the award-winning children’s book Howl Like a Wolf! and the game Guess My Animal! which both combine ecology, animal behavior, and imagination to engage children in creative play. She’s a former scriptwriter for the educational programs SciShow and Crash Course, and prior to that worked as a wildlife field biologist. She lives outside of Glacier National Park, with her family.