The peccary digestive tract is characterised by an elaborate forestomach. In order to further characterise the digestive function of peccaries, we report body mass, digestive organ mass, content mass of the gastrointestinal tract compartments and their length and width, as well as liver, parotis and mandibular gland mass. Our data on eleven collared and four white-lipped peccaries suggest that peccaries have a small relative stomach volume compared to other foregut fermenters, which implies a comparatively lower fermentative capacity and thus forage digestibility. The forestomach could enable peccaries to deal, in conjunction with their large parotis glands, with certain plant toxins (e.g. oxalic acid). The finding of sand being trapped in the forestomach blindsacs could indicate a disadvantage of the peccary forestomach design. The relevance of the forestomach to peccaries remains enigmatic.