The largest rat species
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The largest rat species, both extinct and extant, showcase the incredible diversity and adaptability of rodents. From the massive Phoberomys pattersoni and Josephoartigasia monesi of the past to the impressive African giant pouched rat and greater cane rat of today, these species highlight the evolutionary success of rodents in various environments.
Rats are a diverse group of rodents that vary significantly in size and habitat. Among them, some species stand out due to their remarkable size. This article explores the largest rat species known to science, focusing on both extant and extinct examples.
Extinct Giants
Phoberomys pattersoni
Phoberomys pattersoni is considered one of the largest rodents that ever existed. Discovered in the Upper Miocene of Venezuela, this species had an estimated body mass of around 700 kilograms, which is more than ten times the mass of the largest living rodent, the capybara. The fossil evidence suggests that Phoberomys lived in marginal lagoons and wetlands, and its postcranial features indicate an evolutionary relationship with pakaranas from the South American rodent radiation1.
Josephoartigasia monesi
Another colossal rodent from the past is Josephoartigasia monesi, a species from the family Dinomyidae. This rodent, discovered in the San José Formation in Uruguay, is estimated to have weighed nearly 1000 kilograms, making it the largest rodent ever recorded. The well-preserved skull of Josephoartigasia monesi has provided significant insights into the anatomy of these extinct giant rodents, which lived in estuarine or deltaic systems with forest communities during the Pliocene-Pleistocene epochs2.
Living Giants
African Giant Pouched Rat (Cricetomys gambianus)
The African giant pouched rat, also known as the Gambian pouched rat, is the largest nocturnal rat and is native to Africa. These rats thrive in urban settings and are known for their significant size. They are often kept as pets, and there are concerns about their potential naturalization in non-native regions like the Caribbean8.
Greater Cane Rat (Thryonomys swinderianus)
The greater cane rat is reputed to be Africa’s second-largest rodent. It is a precocial hystricomorph with a unique phenotype and life history. These rats are mainly distributed in the humid and sub-humid regions of sub-Saharan Africa and are of significant scientific and socio-economic interest due to their size and potential for domestication5 6.
Woolly Giant Rat (Kunsia tomentosus)
Kunsia tomentosus, commonly known as the woolly giant rat, is the largest extant sigmondontine rodent. It is semifossorial and typically associated with the Cerrado and Beni domains in central South America. This species is distinguishable by its large size, dark-gray fur, and powerful claws. Although not currently considered threatened, its westernmost populations have presumably been extirpated in the past two centuries7.