Neochoerus aesopi is an extinct species of relatively large rodent that lived in North America during the Pleistocene epoch until its extinction about 12,000 years ago.

Belonging to the subfamily Hydrochoerinae, it is closely related to the modern capybaras of the genus Hydrochoerus.

It weighed about 80 kg, being similar in size to the modern-day capybara.

[1] Hydrochoerus holmesi and several other formerly recognized extinct taxa have been synonymized with N.

[1] Identification of these types of rodent fossils is an inexact science, and lines between various classifications are often questionable.