Whiskers tell a devil of a tale
Scientists can peer at least nine months into a Tasmanian devil’s past by studying its whiskers, a new study led by UNSW Sydney has found.
The long, wiry whiskers on these stocky marsupials hold chemical imprints from food they’ve eaten in the past — records that can help tell broader stories about their foraging habits, habitat use and how they respond to environmental change.
Researchers have now mapped this timescale for the first time, showing that devils’ whiskers can capture seasonal dietary changes over at least nine months and potentially up to a year.
The findings, published in Ecosphere, offer a way to monitor the endangered native species with minimal disruptions to their habitats.
To get a clearer picture of the timeline, the UNSW-led research team fed tablets enriched in heavy stable isotopes — types of atoms that don’t decay into other elements over time — to six captive devils at three-month intervals. These stable isotopes acted as timestamps, marking the whiskers with each season’s passing.
When more than a year had passed, the team removed the longest whisker from each animal for analysis.
They found the whiskers grew fast at first before slowing down, and that whiskers on different parts of the muzzle grew to different maximum lengths. On average, the longest whiskers held at least nine months of the animal’s ecological history — but as whisker growth slows over time, the researchers suggest it’s likely they can hold up to a year.
The team used its findings to create a new whisker analysis model that can help track how the endangered animals — who were recently brought to the edge of extinction — are faring in the wild.
“Tasmanian devil numbers are currently in recovery after the devastating effects of a highly transmissible cancer called the devil facial tumour disease,” study lead author Marie Attard said.
“Since the discovery of this disease in the 1990s, many healthy individuals have been translocated to disease-free areas or are part of captive breeding programs to help boost their numbers,” Dr Attard said.
“This whisker analysis tool will significantly enhance their management in pre-existing and translocated wild populations.”
Devil facial tumour disease doesn’t behave like any type of cancer known to humans.
In fact, this type of cancer — a cancer that’s contagious — is rarely seen in nature at all.
“There are only three instances of transmissible cancer in mammals,” co-author Tracey Rogers said.
“Sadly, the devil facial tumour disease is one of them.”
The disease spreads quickly among devil colonies, passing between the animals as they bite each other while fighting. It has devastated many devil colonies since its discovery in 1996.
Different conservation programs have been designed to help minimise the spread of infection and protect the species, for example by relocating individuals to disease-free areas or creating captive breeding programs to help boost their numbers.
Dr Attard said the findings could help these conservation efforts, whether it was by identifying shifts in individual diet and habitat preferences in wild populations, or helping conservationists select suitable devils for translocation.