|Consequences of tooth wear in reindeer
Age related tooth wear has significant consequences for digestive processes and energy gain in Svalbard reindeer, concludes UNIS Ph.D. candidate Vebjørn Veiberg in his thesis. He will be defending his thesis on patterns, causes and consequences of tooth wear of the Svalbard reindeer on September 21st at the University of Oslo.
Well functioning teeth are essential to food capturing and ingestion for terrestrial mammals. Tooth durability and functionality have thus been regarded as a limiting factor to animal performance and life span. In his Ph.D. Vebjørn Veiberg has studied patterns, causes and consequences of tooth wear using an assemblage of northern deer species.
Presents rare evidence
This work is among the first to actually document quantitative relationships between age related changes in tooth morphology and its effects in terms of reduced digestion efficiency and energetic gain. Though frequently hypothesised, the relationship between age related tooth wear on the one side, and energetic gain and life span on the other, has rarely ever been thoroughly investigated.
This thesis therefore presents rare evidence on the consequences of tooth wear on animal performance in wild populations.
Being the world’s northernmost deer species, the Svalbard reindeer represents a unique opportunity to study adaptations and constraints to ungulate life and physiology in general. (Photo: Erik Ropstad).
The Svalbard reindeer is the northernmost living deer species and the only large herbivore in Svalbard. The climatic conditions and the seasonal variations in food abundance represent great challenges for the reindeer. These factors make the Svalbard reindeer a very interesting species.
Age and weight give significant effect
Material from the UNIS-linked reindeer project was used to study the relationship between tooth functionality, animal age, body mass, various key parameters of ruminant digestion physiology and fat deposition. By using a novel method for extracting information about tooth surface topography, increasing age was found to coincide with reduced chewing efficiency. In addition, heavy younger animals were found to have more worn teeth than lighter ones, indicating that increased growth had a cost in terms of tooth wear.
Increased age and degree of tooth wear resulted in decreased digestion efficiency. Evidence of age related alterations in stomach and stomach content proportions was also discovered. Though these changes may represent compensation to the reduced chewing efficiency, the adaptations were not sufficient to avoid a reduction in animal fat deposition.
Prior evolution vs. present environment
The consequences of evolutionary versus environmental effects on tooth dimensions and tooth wear rates were also investigated, using data from French roe deer populations and Norwegian red deer and moose populations. As predicted from evolutionary hypotheses, expected life span and dietary preferences were found to be of greater importance to tooth dimensions and wear patterns than present environmental conditions.
The Ph.D. of Vebjørn Veiberg has been financed by University Centre in Svalbard (UNIS). The work has been carried out in close collaboration with both national (University of Oslo; Norwegian Institute for Nature Research) and international institutions (Macaulay Institute, Aberdeen; University of Lyon). In February 2008 Veiberg starts as a researcher at the Norwegian Institute for Nature Research and will continue his research activity on arctic and temperate ungulates.