Wear Fast,Die Young: More Worn Teeth and Shorter Lives in Iberian Compared to Scottish Red Deer

Teeth in Cervidae are permanent structures that are not replaceable or repairable; consequently their rate of wear, due to the grinding effect of food and dental attrition, affects their duration and can determine an animal''s lifespan. Tooth wear is also a useful indicator of accumulative life energy investment in intake and mastication and their interactions with diet. Little is known regarding how natural and sexual selection operate on dental structures within a species in contrasting environments and how these relate to life history traits to explain differences in population rates of tooth wear and longevity. We hypothesised that populations under harsh environmental conditions should be selected for more hypsodont teeth while sexual selection may maintain similar sex differences within different populations. We investigated the patterns of tooth wear in males and females of Iberian red deer (Cervus elaphus hispanicus) in Southern Spain and Scottish red deer (C. e. scoticus) across Scotland, that occur in very different environments, using 10343 samples from legal hunting activities. We found higher rates of both incisor and molar wear in the Spanish compared to Scottish populations. However, Scottish red deer had larger incisors at emergence than Iberian red deer, whilst molars emerged at a similar size in both populations and sexes. Iberian and Scottish males had earlier tooth depletion than females, in support of a similar sexual selection process in both populations. However, whilst average lifespan for Iberian males was 4 years shorter than that for Iberian females and Scottish males, Scottish males only showed a reduction of 1 year in average lifespan with respect to Scottish females. More worn molars were associated with larger mandibles in both populations, suggesting that higher intake and/or greater investment in food comminution may have favoured increased body growth, before later loss of tooth efficiency due to severe wear. These results illustrate how independent selection in both subspecies, that diverged 11,700 years BP, has resulted in the evolution of different longevity, although sexual selection has maintained a similar pattern of relative sex differences in tooth depletion. This study opens interesting questions on optimal allocation in life history trade-offs and the independent evolution of allopatric populations.     

Activity patterns in moose and roe deer in a north boreal forest

The activity patterns of a coarse browser, the moose. Alces alces , and a selective browser, the roe deer, Capreolus capreolus . in a north boreal forest, central Sweden, were compared with respect to time allocated for foraging and processing (ruminating) in different seasons. Data were quantified by measuring 24 h activity patterns which included both the duration and frequency of active and inactive periods. Activity patterns were measured from 9 female moose and 9 roe deer that were radiomarked during April 1974–May 1978 (roe deer) and February 1982–December 1984 (moose). In total, data were available from 4345 h for roe deer and 14745 h for moose. Roe deer differed from moose in having active bouts more evenly distributed over the day. Generally, both species were most active during sunrise and sunset. Total daily active time varied with season, reaching the highest value in late May – early June among roe deer (56.7% of the day) and a month later among moose (51.9%). Both species were least active in February (30–40%). Average length of active bouts did not differ significantly between the species but changed with season (roe deer 48.6–99.2 min, moose 61.6–88.7 min). Average length of inactive bouts varied significantly with season, with moose having consistently longer bouts (89.3–156.3 min) than roe deer (55.8–107.0 min). The number of activity bouts per day were also higher among roe deer. During midsummer, they changed activity nearly twice as many times as moose (26 times d⁻¹ vs 16 times d⁻¹).     

Effects of age, sex and density on body weight of Norwegian red deer: evidence of density-dependent senescence

There are only a few recent studies that have demonstrated senescence in ungulates and nothing is known regarding how patterns of senescence may vary as a function of density Senescence in general is linked to the cost of reproduction, which probably increases with density in ungulates and may differ between the sexes. Further, senescence in ungulates is also regarded to be a function of tooth wear rates. As density dependence and sexual differences in food choice have been well documented, this may lead to different tooth wear rates and, thus, possibly density-dependent and sex-specific patterns of senescence. We therefore investigated the effects of age, sex, density and their possible interactions on the variability of body weight in 29,047 red deer harvested during 1965-1998 from Norway, out of which 380 males and 1452 females were eight years or older. There was clear evidence that spatio-temporal variation in density correlated negatively with body weights. In addition, there was evidence of senescence in both male and female red deer. Age at onset of senescence in females was after 20 years of age and independent of population density. In males, the onset and rate of senescence increased with increasing population density. The onset of senescence for males was at ca. 12 years of age at low density, but decreased to approximately ten years of age at high density. The pattern of density-dependent senescence in males, but not that in females, can be explained if (i) the cost of reproduction increases with density more strongly in male than in female red deer, and/or (ii) tooth wear rates are density dependent in males, but not in females. We discuss the ability of these two different, not mutually exclusive hypotheses in explaining the observed pattern of senescence.     

Decelerating and sex-dependent tooth wear in Norwegian red deer

In ungulates, tooth wear is often suggested as a proximate cause of senescence. Tooth wear is expected to be sex-dependent since energetic requirements and food selection varies largely between sexes in sexually dimorphic ungulates. Furthermore, tooth wear may lower mastication efficiency, and we predict a negative correlation between tooth wear and body weight or condition. We tested these predictions on data on tooth wear (estimated as height of first molar) of 1,311 male and 1,348 female red deer ( Cervus elaphus) aged 3-25 years and harvested along the west coast of Norway. The rate of tooth wear decreased with age. Males wear teeth at a higher rate (from 0.61 mm/year in 4-year olds to 0.45 mm/year in 11-year olds) than females (from 0.52 mm/year in 4-year olds to 0.39 mm/year in 11-year olds). Molar height correlated positively with body weight in both sexes, but not after adjusting for body size. Molar height was strongly dependent on body size in 3-year-old individuals (when tooth wear is minimal). Earlier reports in the literature of a positive correlation between tooth height and body weight may therefore be due to initial size differences rather than differences in condition due to tooth wear.     

Bigger teeth for longer life? Longevity and molar height in two roe deer populations

The role of tooth wear as a proximate cause of senescence in ruminants has recently been highlighted. There are two competing hypotheses to explain variation in tooth height and wear; the diet-quality hypothesis predicting increased wear in low-quality habitats, and the life-history hypothesis predicting molar height to be related to expected longevity. We compared tooth height and wear from roe deer of known age from two contrasting populations of roe deer (Capreolus capreolus) in France: Trois Fontaines (TF) with good habitat and shorter animal life expectancy and Chizé (CH) with poor habitat and longer animal life expectancy. There was no population difference in tooth wear, leading to rejection of the diet-quality hypothesis. However, despite their smaller body size, initial molar height for animals from CH was larger than for animals from TF. This provides the first evidence that variation in longevity between populations can lead to differences in molar height within a species.     

Geographical and latitudinal variation in growth patterns and adult body size of Swedish moose (Alces alces)

We examined the geographical pattern in growth and adult body size among 14 populations of Swedish moose (Alces alces) using data from 4,294 moose (1.5 years old) killed during the hunting season in 1989–1992. In both sexes, adult body mass was significantly positively correlated with latitude. Moose in northern populations had a 15–20% larger adult body mass than moose in the south. Juvenile body mass was correlated with neither latitude nor adult body mass. Thus, variation in time (years) and rate of body growth after the juvenile stage were responsible for most of the variation in adult body mass among populations. Moose in northern populations grew for approximately 2 more years of life than southern moose. In contrast to adult body mass, skeletal size (measured as jawbone length) was not correlated with latitude, suggesting that variation in adult body mass was primarily due to differences in fat reserves. Discrimination between population characteristics, such as moose density, climate, and the amount of browse available to moose, showed climatic harshness to be the most important variable explaining geographical variation in body mass among populations. The results support the notion that in mammals body size increases with latitude in accordance with Bergmann's rule. We conclude that (1) variation in patterns of growth after the juvenile stage is the main cause of the latitudinal trend in adult body size in moose, and (2) climatic conditions are a more important factor than population density and availability of food in explaining geographical variation in growth patterns and adult body mass between populations of Swedish moose.     

Influence of size and density of browse patches on intake rates and foraging decisions of young moose and white-tailed deer

We examined the functional response and foraging behavior of young moose (Alces alces) and white-tailed deer (Odocoileus virginianus) relative to animal size and the size and distribution of browse patches. The animals were offered one, three, or nine stems of dormant red maple (Acer rubrum) in hand-assembled patches spaced 2.33, 7, 14, or 21 m apart along a runway. Moose took larger twig diameters and bites and had greater dry matter and digestible energy intake rates than did deer, but had lower cropping rates. Moose and deer travelled at similar velocities between patches and took similar numbers of bites per stem. We found that a model of intake rate, based on the mechanics of cropping, chewing, and encountering bites, effectively described the intake rate of moose and deer feeding in heterogeneous distributions of browses. As patch size and density declined, the animals walked faster between patches, cropped larger bites, and cropped more bites per stem, and hence, dry matter intake rates remained relatively constant. As is characteristic of many hardwood browse stems, however, potential digestible energy concentration of the red maple stems declined as the size and number of bites removed (i.e., stem diameter at point of clipping) by the animals increased. Therefore, the digestible energy content of the diet declined with decreasing patch size and density. Time spent foraging within a patch increased as patch size increased and as distance between patches increased, which qualitatively supported the marginal-value theorem. However, actual patch residence times for deer and moose exceeded those predicted by the marginal-value theorem (MVT) by approximately 250%. The difference between actual and predicted residence time may have been a result of (1) an unknown or complex gain function, (2) the artificial conditions of the experiments, or (3) assumptions of MVT that do not apply to herbivores.     

Fast and efficient DNA-based method for winter diet analysis from stools of three cervids: moose, red deer, and roe deer

Effects of cervid browsing on timber production, especially during winter, lead to economic losses in forest management. The aim of this study was to present an efficient DNA-based method which allows qualitative assessment of the winter diet from stools of moose (Alces alces), roe deer (Capreolus capreolus), and red deer (Cervus elaphus). The preliminary results of the diet composition of the three cervids from Poland were also presented with a special emphasis on moose. The electropherograms of the chloroplast intron trnL (UAA) P6 loop amplification products using g (fluorescence-labeled) and h primers revealed differences in the length of PCR products among various plant species eaten by these herbivores. In addition, the usage of species-specific primers allowed unambiguous identification of different gymnosperms and angiosperms. The preliminary moose diet analysis, based on winter fecal samples from the entire range of moose occurrence in Poland, revealed the presence of 15 to 24 tree, shrub, and herbaceous species. This fast, cost-efficient, and simple method proved also to be reliable for the diet analysis of red deer and roe deer. It may be a valuable tool in forest and conservation management, as well as a way of enhancing ecological studies focusing on the impact of herbivores on the ecosystems and their possible food niche overlap.     

Antibodies to ruminant alpha-herpesviruses and pestiviruses in Norwegian cervids

A serologic survey revealed that Norwegian populations of free-ranging reindeer (Rangifer tarandus tarandus), roe deer (Capreolus capreolus), red deer (Cervus elaphus), and moose (Alces alces) have been exposed to alpha-herpesviruses and pestiviruses. A total of 3,796 serum samples collected during the period 1993-2000 were tested in a neutralization test for antibodies against bovine herpesvirus 1 (BHV-1) or cervid herpesvirus 2 (CerHV-2), and 3,897 samples were tested by a neutralization test and/or enzyme-linked immunosorbent assay for antibodies against bovine viral diarrhea virus (BVDV). Antibodies against alpha-herpesvirus were found in 28.5% of reindeer, 3.0% of roe deer, and 0.5% of red deer, while all moose samples were negative. In reindeer, the prevalence of seropositive animals increased with age and was higher in males than females. Antibodies against BVDV were detected in 12.3% of roe deer, 4.2% of reindeer, 2.0% of moose and 1.1% of red deer. The results indicate that both alpha-herpesvirus and pestivirus are endemic in reindeer and pestivirus is endemic in roe deer in Norway. The viruses may be specific cervid strains. Seropositive red deer and moose may have become exposed as a result of contact with other ruminant species.     

The relationship between tooth wear, habitat quality and late-life reproduction in a wild red deer population

1. Molar tooth wear is considered an important proximate mechanism driving patterns of senescence in ungulates but few studies have investigated the causes of variation in molar wear or their consequences for reproductive success. 2. In this study, we assessed molar tooth wear at death among red deer Cervus elaphus of known age on the Isle of Rum, Scotland. 3. First molar height showed a decelerating decline with age. In females, the rates of molar wear with age varied with location of home range and individuals experiencing low resource competition showed reduced molar wear. We suggest that this spatial variation in molar wear is related to differences in the availability of high-quality grazing habitat and levels of resource competition. 4. There was no evidence that females with more heavily worn molars had reduced reproductive performance late in life or that first molar height was associated with reproductive senescence.     

Activity patterns and resource use by sheep and red deer grazing across a grass/heather boundary

Diet selection and activities of sheep and red deer grazing alone and together across a grass (primarily Lolium perenne/Agrostis capillaris ) and heather ( Calluna vulgaris ) boundary, between July and October, are described.
Throughout the experiment, both animal species had a much higher proportion of grass than heather in their diet. Time spent grazing on each type of vegetation was similarly greater on grass, and the bite rates of the animals were also more rapid on the grass than on the heather.
Red deer spent more time grazing per 24 hours than did sheep, with sheep grazing less during darkness hours than red deer. Total grazing time of both species did not decrease with decreasing daylength from July to October.
There were no consistent differences in the diurnal patterns of activity of sheep and red deer, with both species showing 2-3 large grazing peaks per day.
There were no consistent effects of mixing sheep and deer on their grazing behaviour and diet composition.     

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

A novel, simple, and objective method is presented for ageing roe deerCapreolus capreolus (Linnaeus, 1758) evaluated on 471 lower jaws from roe deer of known age (351 with permanent premolars). It is based on tooth eruption patterns and presence/absence of wear characters in jaws from roe deer integrated in a scoring system. Permanent cheek teeth emerge in May–July in the year af ter birth, which enables precise age determination of individuals with deciduous premolars. For individuals with permanent cheek teeth, the method provides the correct age for all individ uals younger than 13 months and > 80% of all individuals between 13 and 24 months old. For older in dividuals the accuracy decreases, but decent accuracy is achieved to the age of 48 months. Males have higher wear rates than females corroborating recent documentation of sex-specific life history tactics in ungulates. The data originate from two separated Danish roe deer populations exposed to contrasting habitats, but no difference in wear rate is found between populations. Thus, previous concern about the validity of age determination methods based on tooth wear may have been overstated. The findings demonstrate that objective measures of tooth wear can provide the basis for age determination in ungulate species that are otherwise difficult to age.     

Hair-loss epizootic in moose (Alces alces) associated with massive deer ked (Lipoptena cervi) infestation

Deer keds (Lipoptena cervi) are blood-sucking flies in the family Hippoboscidae; moose (Alces alces) are their main host in Scandinavia. There are no detailed reports of the negative impacts of deer keds on moose. In 2006 and 2007, hunters in southeastern Norway and midwestern Sweden found several moose cadavers with severe alopecia; numerous moose had extensive hair loss. Between February 2006 and June 2007, materials from 23 moose were submitted for laboratory examination and large numbers of deer keds were found in the coat of most animals. The body condition of the moose varied but was poor in animals with severe alopecia. The findings of enormous numbers of deer keds in the coat of the majority of the affected animals and a consistent histologic image (acute to chronic, multifocal to coalescing, eosinophilic to lymphocytic dermatitis), concurrent with the absence of any other lesions, trace element deficiencies, or dermal infections which are known to cause alopecia, suggest that the hair-loss epizootic was linked to massive infestations with deer keds. The emergence of this hair-loss syndrome implies that the dynamics between parasite and host have been disrupted by a currently unknown environmental or ecological factor. A high moose density, combined with extraordinarily mild weather June 2006-June 2007 and a particularly long period with the absence of night-frost in autumn of 2006, may have been ideal for deer ked development, survival, and optimal host acquisition.     

Malignant catarrhal fever in free-ranging cervids associated with OvHV-2 and CpHV-2 DNA

Pathologic lesions were summarized in 18 free-ranging cervids (15 moose [Alces alces], two roe deer [Capreolus capreolus], and one red deer [Cervus elaphus]) diagnosed with malignant catarrhal fever (MCF) after examination at the National Veterinary Institute, Oslo 1982-2005. Eye lesions (conjunctivitis, corneal opacity, fibrin clots in the anterior eye chamber) were the most frequent gross finding. Erosive-ulcerative mucosal lesions in the nose and mouth were also commonly found. Histopathology revealed a nonpurulent vasculitis and perivasculitis in the central nervous system (CNS) typical of MCF in 16 of the cases. The diagnosis in the remaining two animals was based upon histologic eye lesions consistent with MCF (CNS not available for examination). Polymerase chain reaction was run on samples from 15 individuals for evidence of MCF-virus DNA, and ovine herpesvirus-2 (OvHV-2) DNA was detected in five moose, one roe deer, and one red deer, and caprine herpesvirus-2 (CpHV-2) DNA was detected in two moose and one roe deer. Sera from 1,000 free-ranging cervids were tested for specific antibodies to MCF-associated viruses (MCFV) by competitive inhibition enzyme-linked immunosorbent assay. The seroprevalences were: red deer 5%, reindeer (Rangifer tarandus) 4%, roe deer 2%, and moose 0.4% (n = 250 for all four species). The results indicate that sheep and goat MCFV may cause serious disease in wild moose, roe deer, and red deer. The seropositive cervids most likely represent individuals infected with either OvHV-2 or CpHV-2, but may also reflect infections with other related MCFV.     

Belovsky's model of optimal moose size

Belovsky's (1978) model for optimal size in moose is applied to red deer. Criticisms are levelled at Belovsky's model. In particular, the equation he derives relating net energy intake to body weight is shown to be fundamentally invalid. Modifications are suggested using existing published information and an analysis of previously unpublished data on red deer stomach size as a function of body weight. I conclude that quantitative predictions of optimal body size are likely to be very difficult as slight changes in the relevant parameters lead to huge changes in predicted optimal weights.     

Antibodies to granulocytic Ehrlichia in moose, red deer, and roe deer in Norway

Serum samples from 104 moose (Alces alces), 124 red deer (Cervus elaphus) and 114 roe deer (Capreolus capreolus), collected from different counties in southern Norway from 1994 to 2000, were analysed by an indirect immunofluorescent antibody staining method for antibodies to Ehrlichia equi. The overall seroprevalences for granulocytic Ehrlichia spp. in moose, red deer, and roe deer from Ixodes ricinus infested counties were 43%, 55%, and 96%, respectively. Antibody prevalence was significantly higher in roe deer than in moose and red deer (P < 0.001). Mean antibody titers (log10 +/- SD) to E. equi in sera from moose, red deer, and roe deer were 1:1,497 (3.17 +/- 0.646), 1:234 (2.37 +/- 0.424) and 1:676 (2.83 +/- 0.404), respectively. The present work indicates that all these wild ruminant species are exposed to granulocytic Ehrlichia in Norway.     

Serologic survey for antibodies against Mycobacterium a vium subsp. paratuberculosis in free-ranging cervids from Norway

Affinity between protein-G and immunoglobulins from red deer (Cervus elaphus), moose (Alces alces), roe deer (Capreolus capreolus), and reindeer (Rangifer tarandus tarandus) was tested in a competition binding assay. Sera from red deer, reindeer, and moose inhibited the assay less than sera from cattle (less affinity), whereas sera from roe deer showed a slightly higher affinity to protein-G than did sera from cattle. The conclusion was made that protein-G could be used instead of anti-species antibodies for these cervid species, where the aim of the screening was to look for exposure or lack of exposure to mycobacteria in the tested populations. Serologic screening of 1,373 free-ranging cervids for antibodies against Mycobacterium avium subsp. paratuberculosis was conducted. All sera were tested by a protein-G-based antigen-absorbed enzyme-linked immunosorbent assay (ELISA). Seropositive moose (10/537; 1.9%), red deer (14/371; 3.8%), roe deer (6/49; 12.2%), and semidomesticated reindeer (11/325; 3.4%) were found, whereas wild reindeer (n = 91) were seronegative. In addition, the red deer sera were tested with a commercial ELISA, by which two animals tested positive and nine were suspicious of having M. avium subsp. paratuberculosis antibodies. Tissue samples and feces from 10 moose originating from a population with a clustering of seropositive animals were investigated by histology and bacteriology with negative results. Paratuberculosis has never been diagnosed in free-ranging or farmed cervid species in Norway. Thus, further studies are indicated to prove that the present findings reflect an infection with M. avium subsp. paratuberculosis.     

Diet overlap among ruminants in Fennoscandia

Information on overlap in resource use is central to understanding of interspecific exploitation competition and resource partitioning. Despite this, measures of diet overlap among northern ruminants in Fennoscandia is limited to one earlier study (reindeer and sheep). Diet overlap between sympatric moose and roe deer calculated with Schoener’s index was 20.7% and 33.6% during summer (data from one area) and winter (data from two areas), respectively, whereas average diet overlap between moose and red deer was 32.0% during winter (data from four areas). Diet overlap between a coastal island population of red deer and sheep was 59.3% during summer and 63.9% during winter. Summer diet overlap between a sheep and a goat population and a sheep and a reindeer population calculated with data on main types of forage plants was 77.0% and 55.1%, respectively. However, overlap calculated with main plant groups was sometimes considerably higher than when calculated for individual forage species. Neither difference in feeding type nor body mass successfully predicted diet overlap between species pairs (n=9), although there tended to be negative correlation (r _p =–0.586, P=0.098) between diet overlap of main plant groups (calculated across studies) and difference in feeding type. Received: 19 October 1999 / Accepted: 31 January 2000     

Experimental Narthecium ossifragum nephrotoxicity in cervids from Norway

One moose (Alces alces), two red deer (Cervus elaphus), two reindeer (Rangifer tarandus) and two fallow deer (Dama dama) were dosed intraruminally with an aqueous extract made from 30 g of bog asphodel (Narthecium ossifragum) (wet weight) per kg live weight. The moose and one of the two reindeer were mildly depressed and had reduced appetite 3 to 7 days and 1 to 4 days after dosing, respectively. The serum creatinine and urea concentrations increased markedly in the moose and red deer, and moderately in the reindeer. No increase in serum creatinine and urea was observed in the fallow deer. Histopathological examination of the kidneys of the animals, killed 8 to 10 days after dosing, revealed tubular epithelial cell degeneration, necrosis, and regeneration in the moose, red deer and reindeer. The renal lesions were severe in the moose, moderate in the red deer and mild in the reindeer. No histopathological lesions were seen in the kidneys of the fallow deer.     

Evidence for a trade-off between early growth and tooth wear in Svalbard reindeer

Ruminants depend on efficient physical degradation of forage through chewing to increase the surface area of the food particles presented to the microflora. Fossil evidence suggests that increased molar height is an adaptation for wear tolerance in dry ecosystems with sparse vegetation, but no study has shown selection pressure for hypsodonty in contemporary ruminants. We explored the relationships between particle size in rumen, tooth wear (scanned molar occlusal topography), age and body mass of female Svalbard reindeer living in an arctic desert at 78 degrees latitude on Svalbard. We predicted that (H1) if the rumen particle size is determined mainly by constraints due to tooth wear, and if tooth wear is mainly a function of age, average particle size in rumen should increase with age. From allometric relations it is known that larger individuals can survive on a lower-quality diet, we therefore predicted (H2) larger particle sizes with increases in (ln) body mass, irrespective of age and wear. Lastly, if there is a trade-off between growth and tooth wear in dry ecosystems (a selection pressure for hypsodonty), we predicted (H3) that teeth of heavier animals should be more worn than those of lighter animals of the same age. The proportion of small particles (<1.0 mm) decreased rapidly with increasing age (consistent with H1). Heavier females within an age class had more worn teeth (consistent with H3) than lighter ones. A close-to-isometric relationship between particle size and body mass suggested that heavier animals partly compensated for reduced tooth efficiency by chewing more. We provide the first evidence of a trade-off between fast early growth and wear (a somatic cost) of a senescence-related trait--the structure and height of the molar--in a wild ruminant inhabiting an arctic desert where selection pressure for increased tooth height is expected. This suggests that foraging conditions are more extreme than the environment in which the species originally evolved.