Meet the small Patagonian monito, a ‘living fossil’ from the ancient past

Written by Javed Iqbal

But it is the monitor’s ability to slow down its body functions to survive the region’s harsh winters that has fascinated scientists such as biologist Roberto Nespolo, a professor who studies animal metabolism at the Austral University of Chile.

When the weather turns cold, the bug-eyed monito builds a mossy nest in a hole in the tree. It gets cozy with four to eight other monitors and settles in for the winter. There, the small marsupial enters what Nespolo described as a death-like torpor, and its heart rate drops from 200 beats per minute down to 2 or 3 beats per minute. In this inactive state, it conserves energy, breathing only every three minutes. Its blood stops circulating.

“I became interested (in the monitor) because of this marsupial’s amazing ability to reduce (its) metabolism and conserve about 95% energy during torpor,” Nespolo said via email. His work is featured in the new CNN Original Series “Patagonia: Life on the Edge of the World.”

“This is what we measured … in the laboratory. Now we were able to replicate these measurements in nature and found that this capacity is even greater. Monitos could hibernate at zero degrees (Celsius) without damaging their tissues! “

Biologist Roberto Nespolo of the Austral University of Chile holds a monito del monte, a forest-dwelling marsupial native to Patagonia in South America.
Nespolo has made it his life’s work to understand how these tiny creatures on the southwestern tip of South America accomplish this feat, something that could help us better understand human metabolism and perhaps even help us find solutions for long-distance space travel. Space agencies say that if humans want to get to Mars, figure out how to induce hibernation in astronauts could be the best way to save mission costs, reduce the size of spacecraft and keep the crew healthy.

“Natural hibernators have a number of physiological adaptations that allow them to almost stop metabolism without damage and to wake up weeks later perfectly fine,” he said.

“So many colleagues are looking to identify the mechanisms to be used either for potential human dormancy or also for medical applications such as organ preservation.”

Monitos (Dromiciops gliroides) hibernate together in a nest.

The monitor is a zoological curiosity in more ways than one.

Like kangaroos and koalas, it is a marsupial that raises its young in pouches. However, the monito is more closely related to its Australian brethren than other marsupials, such as the opossums that live in the Americas – something that has long puzzled scientists.

Scientists consider the two species of monito (Dromiciops gliroides and D. bozinovici) to be essentially living fossils – part of a genus called Microbiotheria that is ancestral to Australian and American marsupials, making them the only living representative of an animal group long thought extinct.

As a “relic species,” the monito acts as a window into the past that can help scientists understand how they have survived for so long, Nespolo’s research has suggested.

The temperate forest habitat where the monito lives is shrinking, but Nespolo is confident the tiny creature, whose direct ancestors once roamed Earth’s ancient supercontinent Gondwanaland, will continue to thrive.

“I’m hopeful for the monitor because they’re very resilient. They’re able to adapt to changes as long as their habitat still exists,” Nespolo said on the CNN Original Series.

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Javed Iqbal

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