[4] In 1792, he published The Animal Kingdom, the first two volumes of a four-tome translation of Linnaeus' Systema Naturae, which is often cited as the taxonomic authority for a great many species.
Out of economical necessity he began writing again in 1809, publishing a variety of minor works, for instance a General View of the Agriculture of Berwickshire.
His last work was a translation of Cuvier's Recherches sur les ossements fossiles de quadrupedes, which was published after Kerr's death under the title "Essays on the Theory of the Earth".
His other works included a massive historical study entitled A General History and Collection of Voyages and Travels in eighteen volumes.
Kerr began the series in 1811, dedicating it to Sir Alexander Cochrane, K.B., Vice-Admiral of the White.