Scientists Are Using Animal Poop to Save One of the World’s Rarest Marsupials

Saving Gilbert’s potoroo means finding habitats rich in the underground fungi it eats.

Gilbert’s potoroo, a rabbit-sized marsupial once thought extinct, survives in only a few protected pockets. It doesn’t eat like most animals. More than 90% of its diet consists of fungi, much of it buried underground like truffles. That strange appetite has made conservation harder.

To save a species like this, you need to ensure good habitats for it. But for Gilbert’s potoroo, that’s not as simple as finding land without foxes, cats or fire. But it’s not easy to tell where these fungi are because they’re buried.

Now researchers say the animal’s future may depend, in part, on a less glamorous clue: scat.

By reading fungal DNA preserved in droppings from Gilbert’s potoroos and other native mammals, scientists are trying to work out which landscapes contain the hidden food webs needed to support new populations. The approach could help conservationists choose better release sites for this extremely endangered species.

Fungus DNA

Gilbert’s potoroo is now confined to a handful of protected refuges in Western Australia. For a species living this close to the edge, conservationists often turn to translocations — moving animals into suitable new habitats to create backup populations in case disaster strikes the remaining wild groups.

But translocations can fail when the new home does not provide what the species actually needs.

“We are looking to recover the species through translocations, which is moving organisms from one location to another to create an insurance population in case anything was to happen in their existing populations,” said lead author Rebecca Quah from Edith Cowan University.

Quah and her colleagues used a techniqued called environmental DNA metabarcoding. They analyzed fungal DNA in scat samples from Gilbert’s potoroos and three mammals that share parts of its world: the quokka, quenda and bush rat.

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The study included scat collected from 2003 to 2024. The researchers extracted DNA, sequenced fungal genetic markers and compared the results with fungal reference databases.

“Traditionally, researchers would go through undigested material in scats to study animal diets, but trying to identify fungal spores remained a challenge,” Quah said. “This research used a molecular technique, known as eDNA metabarcoding to decipher what animals are eating. It’s a non-invasive way of studying diet and all you need are fresh scats from the environment.”

Across all four mammals, the researchers detected 456 fungal genetic variants. After removing fungi likely to represent accidental consumption, contamination or gut microbes, 115 remained as likely dietary fungi.

A Varied Diet

The potoroo had the broadest fungal diet by far.

Researchers found 105 fungal variants in Gilbert’s potoroo scat, compared with 41 each in quokka and quenda, and 37 in bush rat. The potoroo also showed the highest fungal richness and diversity at both study sites.

That finding fits the animal’s reputation as a true fungal specialist. But it also showed why no single companion species can stand in for the potoroo.

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Quokkas have long seemed promising as habitat guides, the hopeful reasoning being that habitats good for quokkas would also be good for the potoroo. This also fits with historical accounts which placed quokkas and potoroos together in dense wet thickets.

The new DNA evidence complicates that picture. Although quokkas may share habitat features with Gilbert’s potoroo, their fungal diet was not the closest match. Quenda and bush rats showed greater dietary similarity in some analyses. At Two Peoples Bay, the potoroo diet differed significantly from quokka and bush rat diets, but not from quenda. At Waychinicup, the diets of all four mammals were more similar.

The lesson isn’t that quokkas are useless as indicators. It is that quokkas alone are not enough.

So How Does This Help the Potoroo?

The researchers propose a broader, more cautious plan: use quokka, quenda and bush rat together as a composite indicator. Each species samples the fungal community in a different way. Taken together, their scats can help reveal whether a potential release site contains the kinds of fungi Gilbert’s potoroo may need.

So, basically, where you find all these animals, the potoroo is more likely to thrive. Though this won’t replace the need for field checks, researchers warn, it could help conservationists shortlist the most promising places before moving animals.

The study also shows that the potoroo is actively supporting its ecosystem. By eating underground fungi and dispersing spores in its droppings, it likely helps fungi spread. Those fungi, in turn, support plant growth and nutrient cycling.

This is a creature worth saving, and the study is a small step in the right direction.