Global representation of rodents in zoological institutions: Implications for ex situ conservation

Rodentia is the most species-rich order of mammals, exhibiting diverse morphology and ecology. Using data from the Zoological Information Management System (ZIMS), this study provides an overview of rodents kept in zoological gardens and other facilities. Of 2,693 rodent species, only 234 (8.69%) are housed in ZIMS institutions, representing 23 of 34 families. Species body-mass appears positively associated with the number of species holdings. While a few species are widespread, over 70% are found in 10 or fewer institutions. Regionally, Asia, Europe, and North America house the most species, with Europe leading in species diversity. However, European institutions have the lowest ratio of native to non-native species. Species assessed as Data-Deficient by the IUCN Red List are less represented ex situ than in the wild (only 3.4% in zoos vs. 15.4% in the wild), and only 9% of zoo-held species are classified as threatened. Most threatened species are kept in less than 10 institutions. Rodent representation in zoological gardens is skewed toward a few widespread, often large-bodied species. This reduced representation potentially hinders the zoological gardens’ education potential. The underrepresentation of threatened rodents in captivity may be a missed opportunity to increase visitors’ awareness of their diversity and conservation needs. Given the feasibility of captive breeding and reintroduction programs for small-sized taxa such as rodents, zoological gardens could probably expand such initiatives.