Lagomorpha

Lore & Background

The name 'lagomorph' derives from Ancient Greek lagos 'hare' and morphē 'form', meaning 'hare shaped'. It was first used in the 19th century and coined by German naturalist Johann Friedrich von Brandt in 1855, who proposed Lagomorpha as a suborder of rodents. The order was formally described as a distinct order by American palaeontologist James W. Gidley in 1912. Earlier, in 1811, Johann Karl Wilhelm Illiger grouped rabbits, hares, and pikas under the name Duplicidentata, based on their shared four upper incisors.

Reader's Guide

Lagomorphs are significant as a distinct mammalian order closely related to rodents, with which they form the clade Glires. Their evolutionary history is not well understood, but fossil records indicate they were far more diverse in the past, with at least twice as many species as today. The order includes rabbits, hares, and pikas, which occupy a wide range of habitats across all continents except Antarctica. Lagomorphs are characterized by continuously growing incisors and cheek teeth, requiring a high-fiber herbivorous diet to prevent overgrowth.

Unlike rodents, they have four upper incisors and lack paw pads, with fur-covered foot soles. Their unique dental and skeletal features, such as a moderately fused postorbital process, distinguish them from other small mammals. The decline of lagomorph lineages in the fossil record highlights ongoing biodiversity loss.