Rodentia are abundant at Early Miocene fossil sites in the Northern Sperrgebiet. The richest concentrations of fossils appear to be due to the activities of carnivores about the size of the extant black backed jackal. Coprolites rich in fossils are found in small patches (up to half a metre diameter) usually within a single stratigraphic layer, suggesting latrine-like behaviour that typifies some extant carnivores which mark their territories by defecating at specific points. Where scats within such concentrations have disintegrated, bones and teeth are more scattered. A particularly rich and taxonomically diverse concentration of micromammal skeletons at Elisabethfeld appears to have accumulated in a burrow, perhaps due to the actions of a small carnivore. Four separate partial skeletons of Bathyergoides possibly represent individuals that died within their burrows. Stromer's pioneering studies of rodents from the Sperrgebiet led to the identification of 8 species. A few additional taxa were described by Hopwood and later by Lavocat. The much augmented collections made by the Namibia Palaeontology Expedition (over 2100 cheek teeth, many of which are in mandibles and maxillae) includes 15 species of which three are new species belonging to new genera. The fauna is remarkable for the presence of three genera of pedetids, four of bathyergids and two of diamantomyids and for the low diversity of Myomorpha. Several of the rodent taxa described from the Northern Sperrgebiet have been identified in Early Miocene deposits of Kenya and Uganda, indicating widespread distribution of certain lineages at the time, and providing evidence of a biochronological nature which suggests that the Namibian deposits are between 21 and 19 million years old. There are indications that Elisabethfeld is the earliest of the Northern Sperrgebiet deposits, followed closely in age by Grillental, and then Langental. All these deposits are earlier in age than the Orange River Valley deposits at Arrisdrift, but Langental is about the same age as Auchas. The rodent faunas from the sites also indicate that the palaeoclimate changed during the Early Miocene with coastal Namibia becoming more arid and its vegetation more open and grassy with the passage of time from Elisabethfeld to Grillental to Langental. The tree cover diminished in phase with the increase in grass cover.