With dainty forelimbs tucked against their fluffy belly and a wonderfully solemn expression on their whiskered face, the sight of a sunbathing mountain viscacha is sure to raise a smile.
This Andean rodent is perplexing and endearing in equal measure, looking as if someone has assembled it from spare parts, with rabbit ears, a squirrel tail and chinchilla fur. And that’s before you’ve seen their cousin, the plains viscacha, that might be likened to a miniature capybara furnished with a Super Mario-style ‘moustache’.
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What is a viscacha?
‘Viscacha’ is a broad common name used for several closely related South American rodents in the family Chinchillidae, which also includes chinchillas.
There are five viscacha species in total, comprising the plains viscacha, Lagostomus maximus, and four mountain viscachas in the genus Lagidium – the northern viscacha, the southern viscacha, Wolffsohn’s viscacha and the newly described Lagidium ahuacaense.
Where do viscachas live?
Mountain viscachas are found in the Andes Mountains, including parts of Peru, Bolivia, Chile and Argentina. They live among rocky slopes, cliffs and outcrops with sparse vegetation, usually at elevations between 4,000 and 5,000m, and shelter in crevices between boulders, rarely straying far from cover.
The plains viscacha, by contrast, lives farther down in the grasslands, pampas and dry scrub of Argentina, Bolivia and Paraguay at elevations up to 3,000m. Colonies dig and occupy vast underground burrow systems.
What do viscachas look like and how big are they?
Confusingly, mountain viscachas look more like long-tailed rabbits than rodents. They sport long ears, large dark eyes and soft fur in shades varying from grey to brown, which helps them to blend into the stony Andean environment. Measuring up to 45cm long, they are surprisingly large but retain an impressive ability to move rapidly over difficult terrain, making impressive leaps between rocks when alarmed.
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The plains viscacha is a stocky character and even larger, reaching up to 66cm long and weighing a hefty 8kg – similar to a Scottish terrier.
The species displays strong sexual dimorphism and the males can be four times larger than the females. It is less agile than the mountain viscachas and built for digging, with powerful forelimbs. The hair is coarse, not fluffy, and bold black-and-white-stripes mark the face, making some individuals (both male and female) appear fetchingly moustached.
Why do mountain viscachas sunbathe?
Unlike the nocturnal plains viscacha, mountain viscachas are diurnal (active during the day) and are often seen perched on exposed rocks around sunrise and sunset, grooming, resting and basking in the warm rays. In the cold, high-altitude habitat of the Andes, sunbathing is likely to help them conserve energy and warm their bodies after chilly nights.
What do viscachas eat?
Viscachas are herbivores. Mountain viscachas feed on whatever plant material is available in their sparse habitats, including grasses, mosses and lichens. Plains viscachas eat grasses, seeds and other vegetation. In farming areas, this appetite has not always endeared them to people, because they may feed on crops and compete with livestock for grazing.
Are they social animals?
Yes. Both mountain and plains viscachas have been found living in large colonies and will warn each other when a predator threatens using high-pitched alarm calls. Plains viscachas build complex burrow systems called viscacheras that can house several dozen individuals. Rather charmingly, plains viscachas are known to gather sticks, stones, bones and other objects around burrow entrances, though scientists are not entirely sure why.
How do viscachas breed?
Female mountain viscachas usually have a single young after a gestation of about three months. Plains viscachas usually have two young after a gestation of about five months, and they are said to be the mammalian species with the highest ovulation rate – up to 326 ova in one reproductive cycle according to scientists. Both species produce young that are relatively advanced, emerging into the world furred and able to nibble solid food very early.
What preys on them?
Wild cats, foxes and birds of prey are all natural predators. Mountain viscachas are a staple food for the Andean mountain cat and make up about 90 per cent of its diet. To evade capture, they rely on quick reactions, agility and powerful hindlegs. Special fleshy pads on their feet, called pallipes, aid their grip and help them move over rocky ground at speed.
The larger and less agile plains viscacha, meanwhile, takes a slightly different approach, spending the daytime hidden away from pumas and pampas foxes within the safety of their underground burrows.
Are viscachas under threat?
Generally, populations are secure, with the northern viscacha, southern viscacha and plains viscacha, all listed as Least Concern by the IUCN. However, plains viscachas have been persecuted as agricultural pests, while some mountain viscachas are hunted locally for meat and fur. More localised species, such as the Wolffsohn’s viscacha and the newly described Lagidium ahuacaense, are harder to assess and may be more vulnerable to habitat disturbance due to their restricted range.
How long do viscachas live?
Mountain viscachas may live about three years in the wild; plains viscachas about 7-8 years
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