Age determination in roe deer — a new approach to tooth wear evaluated on known age in dividuals

Abstract

The need for re li able age de ter mi na tion of mam mals has stim u lated the de vel op ment of a num ber of dif fer ent meth ods (Mor ris 1972). The in flu en tial ce men tum annuli count ing method has been ap plied to most un gu late spe cies eg moose Alces alces (Ser geant and Pimlott 1959), fal low deer Dama dama (Moore et al. 1995), rein deer Rangifer tarandus (Reimers and Nordby 1968) and roe deer Capreolus capreolus (Aitken 1975). This method may be termed ob jec tive, be cause it re lies on the count ing of lines in the den tal ce ment. How ever, few stud ies have in vesti gated the re li abil ity of the ce men tum annuli [205] Acta Theriologica 51 (2): 205-214, 2006. PL ISSN 0001-7051Age de ter mi na tion in roe deer -a new ap proach to tooth wear eval u ated on known age in di vid u als Toke T. HqYE* Hrye T. T. 2006. Age de ter mi na tion in roe deer -a new ap proach to tooth wear eval u ated on known age in di vid u als. Acta Theriologica 51: 205-214.A novel, sim ple, and ob jec tive method is pre sented for age ing roe deer Capreolus capreolus (Linnaeus, 1758) eval u ated on 471 lower jaws from roe deer of known age (351 with per ma nent pre mol ars). It is based on tooth erup tion pat terns and pres ence/ab sence of wear char ac ters in jaws from roe deer in te grated in a scor ing sys tem. Per ma nent cheek teeth emerge in May-July in the year af ter birth, which en ables pre cise age de ter mi na tion of in di vid u als with de cid u ous pre mol ars. For in di vid u als with per ma nent cheek teeth, the method pro vides the cor rect age for all in di vid u als youn ger than 13 months and > 80% of all in di vid u als be tween 13 and 24 months old. For older in di vid u als the ac cu racy de creases, but de cent ac cu racy is achieved to the age of 48 months. Males have higher wear rates than fe males cor rob o rat ing re cent doc u men ta tion of sex-spe cific life his tory tac tics in ungulates. The data orig inate from two sep a rated Dan ish roe deer pop u la tions ex posed to con trast ing hab i tats, but no dif fer ence in wear rate is found be tween pop u la tions. Thus, pre vi ous con cern about the va lid ity of age de ter mi na tion meth ods based on tooth wear may have been over stated. The find ings dem on strate that ob jec tive mea sures of tooth wear can pro vide the ba sis for age de ter mi na tion in un gu late spe cies that are oth er wise dif fi cult to age. Na tional En vi ron men tal Re search In sti tute, De part ment Key words: Capreolus capreolus, age de ter mi na tion, known age, mo lar wear, ob jec tive age cri te ria * Pres ent ad dress: Na tional En vi ron men tal Re search In sti tute, De part ment of Arc tic En vi ron ment,

Evaluation of the eye lens method for age determination in roe deerCapreolus capreolus

“…The percentage of accurate estimates usually decreases in the higher age classes (Rieck 1970, Hewison et al 1999, Hrye 2006. Similarly, eye lens method produces the highest precision in the lowest age classes (Hrabe and Koubek 1989, Gaèiae 2005a, Mysterud and qstbye 2006, which was confirmed by the study results.…”

“…Indeed, the limited success in studies of roe deer age determination based on jaw boards (eg Hewison et al 1999) was explained by the fact that large samples of known age jaws are needed to represent the full range of wear patterns for any given age class (Hrye 2006). Unfortunately, many decades and large financial means are necessary to collect adequate material of known age, especially for the oldest individuals.…”

“…This is especially characteristic of roe deer Capreolus capreolus (Linnaeus, 1758), and for this reason numerous researchers keep looking for simple, but precise and applicable methods. For example, different methods are combined and applied collectively to improve the accuracy (Hell et al 1973, Stubbe et al 1987a or the already existing methods are checked and enhanced (Klejnotowski and £abudzki 1998, Gaèiae 1999, Cicognani and Monti 2000, Hrye 2006, Mysterud and qstbye 2006.…”

“…The results of previous studies on roe deer of known age show that the age estimation, based on the tooth eruption patterns and tooth wear, or the objective criteria (tooth height, colour of dentine and presence/absence of wear characters), of older individuals is less reliable and more difficult than that of younger individuals (Rieck 1970, Stubbe et al 1987b, Hewison et al 1999, Hrye 2006). Further, this best known and most applied method is less precise compared to the cementum layer technique, because of the different degree of tooth wear which occurs between the individuals within the same age class, as well as among the individuals from distinctly different habitats (Szabik 1973, Aitken 1975.…”

Prevalence and distribution of infectious and parasitic agents in roe deer from Spain and their possible role as reservoirs

“…For each animal, sex (43 females and 48 males) and age were registered according to their teeth features (Høye 2006). According to their teeth features, the animals were divided in two age-groups, young (<2 years; n ¼ 25) and adult (>2 years; n ¼ 67).…”