Technically we are not talking about a weasel or an otter (it is an otter-like creature though). This week we are discussing an extinct mustelid reminiscent of its descendants. These happen to be mustelids and/or pinnipeds, depending on the researcher that you ask. Potamotherium was a genus of carnivoran mustelids represented by the single species P. miocenium arising during the so-called "cat gap" of the Miocene. The "cat gap" is a part of the Miocene in which felids are noticeably absent. This era of time allowed other groups, like the mustelids, and Potamotherium, to assert themselves as more apex-like predators. Other large predators still roamed and kept mustelids in check, but the " cat gap" was a very important time in the evolutionary history of the mustelids and pinnipeds. Which group does Potamotherium belong to? We will examine the different opinions and findings that differentiate the placement of this large semiaquatic carnivore during the week. However, the fuzzy terror of other riverine, or maybe just freshwater fishes, was adorable at the same time as being scary and predatory.