Digging Down Under
As alien in appearance as the Martian-like environment it inhabits, the southern marsupial mole (Notoryctes typhlops) spends the majority of its life tunneling beneath Australia’s vast, red deserts. This unforgiving habitat and the animal’s curious way of life requires a whole host of specialized traits. Look closely and you can see delicate, round eyelids. But these lids are fused shut, and they cover eyes that lack both a lens and a pupil—relics of vision long since lost through the process of evolution. To find their way in the perpetual darkness, the mysterious marsupials instead rely on a keen sense of smell and acute hearing tuned to low-frequency sounds.
Various other adaptations make this denizen of the underground a powerful digging machine. Fused neck vertebrae provide bull dozer-like rigidity, while bony armor protects the marsupial mole’s snout as it plows through coarse sand. Lobster-like claws on the forelimbs enable the animal to swipe through even densely-packed sediment, as hind-limbs kick sand and soil backward. When doing what it does best, the energetic digger virtually swims through the sand in search of ants and juicy beetle larvae.
Like so many Australian mammals, female marsupial moles have a pouch in which their young complete their development. But as the only ground-dwelling marsupial, the mole’s pouch is one of a kind—it opens toward the back, an adaptation that protects young moles from being inundated with sand as the mother burrows.
Despite the physical similarities between marsupial moles and true moles, the two lineages are only distantly related, having likely diverged during the Mesozoic Era (65–250 million years ago). Their resemblance is instead a classic example of convergent evolution, a process by which two distantly related species, or groups, evolve similar traits in response to a similar set of environmental conditions.
Tanami Desert, Australia
Mike Gillam is a freelance photographer based out of Alice Springs, a remote gateway town to Australia's desert interior situated in the Northern Territory. Gillam has won numerous awards for his work focusing on preserving arid biodiversity and cultural heritage, including "Nature Photographer of the Year" from Australian Geographic Magazine.
Katie Jewett is a Bay Area science writer, previously at the California Academy of Sciences and now at the Stanford Center for Ocean Solutions, where she loves learning something new about our planet every day. Previously, she spent winters in the Colorado Rockies and summers living and working on the water.