Mammalian Biology

, Volume 76, Issue 5, pp 534–539 | Cite as

Biplanar X-ray motion analysis of the lower jaw movement during incisor interaction and mastication in the beaver (Castor fiber L. 1758)

  • Clara StefenEmail author
  • Peter Ibe
  • Martin S. Fischer
Original Investigation


The first biplanar X-ray motion analysis of mastication and food processing for Castor fiber is presented. While particles are chipped off interaction of incisors involves variable movements of the lower mandible and thus incisors. After jaw opening the tip of the lower incisors can reach different positions anteriorly of the upper incisors. Then the mandible moves upwards and backwards and brings the tips of the incisors into contact. The lower incisors slide along the wear facet of the upper to the ledge when the cheek teeth occlude. The glenoid fossa and lower jaw condyle are in close contact during incisor contact and no transverse movements are observed. Mastication involves interaction of the cheek teeth with no contact of the incisors. When the cheek teeth are in occlusal contact the mandible is moved forward and transverse, or mediolateral. In consecutive power strokes the jaw is moved alternately to the right and left side. When the jaw opens it is brought into a more central but not totally centred position. During mastication the condyles are positioned posteriorly to the glenoid allowing lateral movement of the mandible. The lateral movement is particularly noticeable in the anterior part of the mandible. With the lateral movements of the incisors one glenoid has to move posteriorly, the other anteriorly.


Castoridae Castor fiber Incisor interaction Mastication Power stroke Condyle position 


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Copyright information

© Deutsche Gesellschaft für Säugetierkunde 2011

Authors and Affiliations

  1. 1.Museum für TierkundeSenckenberg Naturhistorische Sammlungen DresdenDresdenGermany
  2. 2.Landesverwaltungsamt Sachsen-AnhaltBiosphärenreservat MittelelbeDessau-RoßlauGermany
  3. 3.Institut für Spezielle Zoologie und Evolutionsbiologie, mit Phyletischem MuseumFriedrich-Schiller-Universität JenaJenaGermany

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