#chinchillidae

[mammalianmammals]

Southern Viscacha (Lagidium viscacia), family Chinchillidae, found in mountainous areas of southern South America.

photograph by Jeremiel

[all-mammal-creechur]

Patagonian Viscacha Lagidium wolffsohni

Locally known as chinchillón anaranjado. This species occurs in southwestern Argentina and adjacent Chile. It occurs up to about 4,000 m (13,000 ft) above sea level. It is found in rocky outcrops in mountainous areas.

img source

[alphynix]

Incamys bolivianus was a caviomorph rodent representing an early member of the chinchillid family, with its closest modern relatives being chinchillas and viscachas.

Living in what is now Bolivia and Argentina during the late Oligocene about 27 million years ago, it inhabited an arid open grassland at a time when the area's climate had drastically cooled due to the formation of the Antarctic Circumpolar Current.

It's estimated to have been similar in size to a large modern chinchilla – weighing around 700g (~1lb 8oz) and measuring about 25-30cm long not including the tail (~10-12").

An endocast of the shape of its brain from a near-complete fossil skull shows that it had a well-developed sense of hearing, particularly in vocalization processing, suggesting it may have been a social animal living in groups communicating with complex calls similar to modern chinchillids. It was probably a ground-dweller less agile than its modern relatives, but still capable of fast movements.

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References:

Bertrand, Ornella C., et al. "The virtual brain endocast of Incamys bolivianus: insight from the neurosensory system into the adaptive radiation of South American rodents." Papers in Palaeontology 10.3 (2024): e1562. https://doi.org/10.1002/spp2.1562

Rasia, Luciano L., Adriana M. Candela, and Carola Cañón. "Comprehensive total evidence phylogeny of chinchillids (Rodentia, Caviomorpha): Cheek teeth anatomy and evolution." Journal of Anatomy 239.2 (2021): 405-423. https://doi.org/10.1111/joa.13430

Wikipedia contributors. “Agua de la Piedra Formation” Wikipedia, 06 Jan. 2025, https://en.wikipedia.org/wiki/Agua_de_la_Piedra_Formation

Wikipedia contributors. “Incamys” Wikipedia, 19 Jan. 2025, https://en.wikipedia.org/wiki/Incamys

[have-you-seen-this-animal]

Long-tailed chinchilla!

Have you seen the long-tailed chinchilla (Chinchilla lanigera)?

I have now

Yes, in photos/videos

Yes, irl

I'm not sure

Voting ended onSep 29, 2025

Historically, these animals were hunted for their coats. Currently they are only found in a small range in the Andes of Northern Chile.

[nightmaresyrup]

Summ Vizzies

A Mountain and Plains Vizcacha

[snototter]

Southern Viscacha (Lagidium viscacia)

by Oscar Fuentes

[briery]

Southern viscachas are colonial animals that live in groups. They do not hibernate and are mostly active soon after dawn and in the evening. Part of their day is spent perched on a rock sunbathing, grooming, or resting. (Via Reddit)

[mastomysowner]