Body mass is one of the most important phenotypic attributes in animal ecology and life history. This trait is widely used in the fields of ecology and macroevolution, since it influences physiology, morphological functions, and a myriad of ecological and social interactions. In this data set, our aim was to gather a comprehensive bird and mammal body mass data set from northern South America. We report body mass, discriminated by sex, for 42,022 individual birds and 7,441 mammals representing 1,317 bird species (69% of Colombia’s avifauna) and 270 mammal species (51% of Colombian mammals) from the Neotropics. The data were sourced from vouchers collected between 1942 and 2020 and from individuals captured and released at banding stations over the last two decades for birds (2000–2020) and the last decade for mammals (2010–2020), by 10 research groups and institutions in Colombia. This data set fills gaps identified in other similar databases, as it focuses on northern South America, a highly diverse Neotropical region often underrepresented in morphological data sets. We provide wide taxonomic coverage for studies interested in information both at regional and local scales. There are no copyright restrictions; the present data paper should be appropriately cited when data are used for publication. The authors would appreciate learning about research projects, teaching exercises, and other uses given to this data set and are open to contribute in further collaborations using these data.

Although taxonomy, ecology, and natural history information of the arboreal spiny rats is available, many gaps in some species distribution still exist. We report here the first records of the Peruvian Toro, Toromys rhipidurus (Thomas, 1928), in southern Colombia. This arboreal spiny rat was only known from the Peruvian Amazonia. These new records extend the known geographical distribution of the species by about 61 km northward from its nearest known locality, at Río Yavarí, Peru. In addition, we provide some notes on the natural history of the species.

La colección de mamíferos del Instituto de Investigación de Recursos Biológicos Alexander von Humboldt es la tercera colección de mayor número de especímenes en el país con 9.471 determinados en 400 especies, 212 géneros, 51 familias y 14 órdenes, procedentes de ocho países, siendo Colombia el de mayor representatividad (66,5% de la diversidad registrada para el país en este grupo). Los órdenes mejor representados son Chiroptera, Rodentia y Primates. Alberga un neotipo y dos paratipos de Cebus albifrons albifrons, un paratipo de Aotus hershkovitzi y un paratipo de Vampyressa sinchi. La colección ha sido un referente para el estudio de mamíferos colombianos y se continúan realizando esfuerzos para mejorar el estado curatorial y la información asociada a los especímenes.