Incisor integrity of North American moose (Alces alces) and possible effects on population age structure

Abstract

For mammals, foraging efficiency and survivorship should be a function of tooth condition. There is evidence the teeth of moose from Cape Breton Island have abnormally high levels of tooth breakage. To address this issue, the objectives of this thesis were to: (1) collect, and quantitatively characterise tooth integrity from several North American moose populations; (2) relate trends in population tooth integrity to population age structure; and (3) determine whether chemistry of teeth affects tooth integrity. It was hypothesised that for moose: (i) decreased cropping efficiency, resulting from a loss of tooth integrity, would compromise energy budgets; therefore negatively affect survivorship; (ii) tooth integrity is influenced by the incorporation of elements into the hydroxyapatite crystal lattice during mineralization.

A total of 3602 individual moose incisors (I1s) were collected from 7 North American jurisdictions from the 2004 and 2005 hunting seasons: New Brunswick (NB), New Hampshire (NH), Ontario (ON), Cape Breton Island (CBI) and Vermont (VT), Newfoundland (NL) and Yukon (YK). Each I1 was characterised in terms of damage, breakage, cracking, wear and incisal depth as an indicator of tooth integrity. A total of 475 incisors from were selected for chemical analysis. Incisor integrity decreased with age at twice the rate for CBI moose relative to NB, NH, ON and VT. However, there was no relationship between loss of incisor integrity and survivorship. A Canonical Analysis of Discriminance demonstrated tooth condition may be influenced by mineral concentration within the enamel.