This note defends the dynamical natural kinds (DNK) hypothesis that some natural kinds are dynamic and correspond to clusters moving in feature space. Philosophers invented the term natural kind for categories that “carve nature at its joints,” i.e., categories that objectively explain the typical features of their instances. The DNK hypothesis is inspired by recent scientific work on classifying technology by statistical analysis and modeling of patent documents (Bedau, Gigliotti et al. 2019), which demonstrated striking non-random movement of technology clusters in a technology feature space. This note describes the DNK hypothesis and summarizes how it is supported by dynamic technology clusters and by the contrast with alternative approaches to natural kinds and biological species.