Functional implications of craniomandibular morphology in African mole-rats (Rodentia: Bathyergidae)

Andrew McIntosh, Philip Graham Cox

Research output: Contribution to journalArticlepeer-review


African mole-rats are subterranean rodents from the family Bathyergidae. The family consists of six genera, five of which (Cryptomys, Fukomys, Georychus, Heliophobius and Heterocephalus) are chisel-tooth diggers, meaning they dig underground using procumbent incisors. The remaining genus of mole-rat (Bathyergus) is a scratch digger, which digs using its forelimbs. Chisel-tooth digging is thought to have evolved to enable exploitation of harder soils. It was hypothesized that to dig successfully using incisors, chisel-tooth digging mole-rats will have a craniomandibular complex that is better able to achieve a large bite force and wide gape compared with scratch digging mole-rats. Linear measurements of morphological characteristics associated with bite force and gape were measured in several chisel-tooth digging and scratch digging mole-rats. Chisel-tooth diggers have increased jaw and condyle lengths relative to their size (characteristics associated with larger gape). They also have relatively wider and taller skulls (characteristics associated with larger bite force). The mechanical advantage of three masticatory muscles of each specimen was also calculated. The mechanical advantage of the temporalis muscle was significantly larger in chisel-tooth digging mole-rats than scratch digging genus. The results demonstrate that chisel-tooth digging bathyergids have a craniomandibular morphology that is better able to facilitate high bite force and wide gape than scratch digging mole-rats.

Original languageEnglish
Pages (from-to)447-462
Number of pages16
JournalBiological Journal of the Linnean Society
Issue number3
Early online date2 Oct 2015
Publication statusPublished - 1 Mar 2016

Bibliographical note

© 2015 The Linnean Society of London. This is an author produced version of a paper accepted for publication in Journal Name . Uploaded in accordance with the publisher's self-archiving policy.


  • Chisel-tooth digging
  • Masticatory biomechanics
  • Scratch digging
  • Subterranean rodents

Cite this