ALCES VOL. 46, 2010 CHILD ET AL. – MOOSE ANTLER MORPHOMETRY 123 MORPHOMETRY OF MOOSE ANTLERS IN CENTRAL BRITISH COLUMBIA Kenneth N. Child1, Daniel A. Aitken2, and Roy V. Rea3 16372 Cornell Place, Prince George, British Columbia V2N 2N7, Canada; 2College of New Caledonia, 3330 22nd Avenue, Prince George, British Columbia V2N 1P8, Canada; 3Natural Resources and Environmental Studies Institute, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia V2N 4Z9, Canada. ABSTRACT: We analyzed the morphometry of 1,965 sets of antlers from hunter-harvested moose (Alces alces andersoni) taken in the central interior of British Columbia. We describe the variation and age-related changes in antler and brow palm form, number of points on both main and brow palms, maximum spread, height and width of palmations, distance between innermost points on the brow palms, and shaft circumference. Architecturally, 25% were cervicorn pole type (PT); 75% were palmicorn with 67% split palm (SP) and 8% full palm (FP). Palmicorn antlers were most common in all age classes. Cervicorn antlers were most common in younger moose (1.5-3.5 years), and rare in moose >4.5 years. Of all antlers collected, 30% had forked brows and 12% had palmated brows. Forked brow palms increased with age; they occurred in 10% of moose 1.5 years old and 40-50% of moose >4.5 years old. The frequency of palmated brow palms increased quickly from 1.5 (2.5%) to 5.5 years (25%), peaked at 13.5 years (40%), before declining in later years. The number of points generally increased from 1.5-7.5 years, and remained stable thereafter. Maximum spread and shaft circumference generally increased from 1.5-13.5 years and decreased thereafter. Maximum antler height and width of main palms increased from 1.5-9.5 years; the first remained stable and the latter declined thereafter. Distance between the inner most points on the brow palms narrowed from 1.5-4.5 years, remained constant to 11.5 years, and then widened thereafter. Antler point counts were the most variable, whereas shaft circumference was the least variable character. ALCES VOL. 46: 123-134 (2010) Key words: Alces alces, brow palm, full palm, main palm, morphometrics, pole type, split palm, sociobiology. Antlers are physiologically and behavior- ally significant to members of the Cervidae, first developing as perennial, but later as de- ciduous protuberances of the skull (Bubenik 1982). Antlers appear to be luxury append- ages that grow on males (and some females) only when other nutritional needs are satisfied (Heffelfinger 2006). The diversity of antler shapes and sizes provides convincing evidence that multiple factors were involved in shaping antlers over time - if antlers served only one purpose, then a single antler shape should have prevailed (Heffelfinger 2006). Antlers are important in sparring and for defense, parading reproductive fitness, condition, and genetic superiority (Bubenik 1982, Heffelfinger 2006), to deflect and amplify sound (Bubenik and Bubenik 2008), and in thermoregulation (Stonehouse 1968). Bubenik et al. (1978) described a pattern of change in antler architecture and complexity relative to design, shape, and size that mir- rored 3 life stages described by Gaillard et al. (2000) as juvenile, prime, and a senescent stage in seniors. The growth and architecture of antler types varies among individuals of a species and between geographically distinct popula- tions, and has been thoroughly described for moose (Alces alces) populations in North MOOSE ANTLER MORPHOMETRY – CHILD ET AL. ALCES VOL. 46, 2010 124 America (Cringan 1955, Timmermann 1971, Bubenik 1973, Bubenik 1982, Child 1982, Van Ballenberghe 1982, Gasaway et al. 1987) and Fennoscandia (Solberg and Saether 1993a, Engan 2001, Nygrén et al. 2007). Antler size is influenced by age, genetic factors, health status, and nutrition (Hibler and Adcock 1971, Wolf 1980, Harmel 1983, Ullrey 1982). For example, Ullrey (1982) indicated that dietary energy restrictions reduce antler volume, shaft diameter, main shaft length, and number of shaft points in 1.5-year old white-tailed deer (Odocoileus virginianus). Therefore, understanding variation in antler types and morphometry in moose populations helps de- termine evolutionary history, sub-speciation, population fitness, and the influence of climatic conditions and habitat quality on antler growth. We describe the age-related morphometry of antler forms and changes in antler architec- tures of moose (A. a. andersoni) from central interior British Columbia. STUDY AREA The Omineca sub-region of the central interior is approximately 122,500 km2 in total area representing ~13% of the total land mass of British Columbia (Fig. 1). Rugged moun- tainous terrain with deeply incised valleys is typical on the northern and eastern sides (Child 1992); in contrast, the terrain is flat to rolling with hundreds of small lakes and wetlands in the southern and western areas (Heard et al. 1997). The sub-region contains extensive areas of important moose habitat in the sub-boreal ecotype. This ecotype is a com- paratively homogeneous unit, located on an extensive drumlinized till plateau surrounding periglacial lake deposits and dissected by many rivers, lakes, and wetlands. Dominant tree species are lodgepole pine (Pinus contorta), white spruce (Picea glauca), and subalpine fir (Abies lasiocarpa). Fires, logging, and insect outbreaks have had major impacts on the forests. Extensive 80-100 year old pine stands were typical of the area during the period in which antlers were collected, and were the result of historical widespread forest fires followed by decades of fire suppression (Child 1992). Clear-cuts created mostly since the 1960s are common throughout the area. Forest succession is characterized by an early shrub stage of 10-25 year duration, and many shrub species are important foods of moose (Heard et al. 1997). The climate is generally wet and cool, with precipitation evenly distributed throughout the year. Mean daily average temperature in the southern portion of the Omineca at Prince George is 4.0o C, ranging from a monthly mean of -9.6o C in January to 15.5oC in July; the mean annual precipitation is 600.8 mm, with 216 cm as snow. In contrast, to the west at Fort Saint James the mean daily average temperature is 3.0o C, ranging from a monthly mean of -11.3o C in January and 15.3o C in July; mean annual precipitation is 487 mm, with 192 cm as snow (Environment Canada 2010). Annual harvest of moose has ranged from 946-1691 animals, averaging of 1340 ± 44 (SD) over 19 years of record. The moose population is considered stable and below carrying capacity; intraspecific competition does not limit per capita food consumption Fig. 1. The Omineca sub-region (Zone A) in central British Columbia. ALCES VOL. 46, 2010 CHILD ET AL. – MOOSE ANTLER MORPHOMETRY 125 (Heard et al. 1997). METHODS From 1982-1989, successful limited entry hunters (LEH, selected by lottery) in central British Columbia were required to submit moose antlers for inspection to study age-related growth and developmental char- acteristics (Child and Aitken 1989); non-LEH hunters (those not selected by lottery) volun- tarily submitted antlers for inspection (Hatter and Child 1992). On each set of antlers the following were measured by one Ministry of Environment technician: antler form - either full palm (FP), split palm (SP), or pole type (PT; Fig. 2), brow palm form (palm, fork, or unclassified palm), and numbers of points on each antler, main palm, and brow form according to Bubenik (1982). An antler tine is defined by regulation (British Columbia Ministry of Environment, 2008-2009 Hunting Regulations) to be a branch of an antler lon- ger than its breadth, at least 2.5 cm in length, and is also called a point (Fig. 3). Number of points on each main palm was calculated to be the difference between the number of points on each antler and the number of points on the corresponding brow. Additionally, maximum spread, maximum antler height (left and right sides), maximum palm width (left and right sides), shaft circumference (left and right sides), and distance between the in- nermost brow points were measured to the nearest mm (Fig. 4). Incisor teeth were col- lected by hunters and sub- mitted to the Ministry of Environment in Victoria, British Columbia. Tooth samples were analyzed by 2 Ministry of Environ- ment technicians. Age was determined by counts of cementum annuli (Sergeant and Pimlott 1969) and stated as calendar age (e.g., 1.5 years). We plotted frequency distributions for all variables in order to identify outliers. We then examined the records for each outlier and deleted those records that were clearly erroneous due to typographical errors; i.e., where measurements were in error by orders of magnitude or errors in transposition of data. After deletions, 1,965 records were available for analysis; we pooled all available data to describe antler morphometrics by age. The Fig. 2. Typical antler forms of moose in the central interior of British Columbia. Fig. 3. Definition of a legal antler point (from British Columbia Ministry of Environment Hunting Regulations Synopsis 2007-2008). MOOSE ANTLER MORPHOMETRY – CHILD ET AL. ALCES VOL. 46, 2010 126 effects of year and area of harvest on antler morphometrics in the same population are being investigated separately. Antlers of SP and FP were tabulated as palmicorn type and antlers of PT were tabulated as cervicorn type (sensu Bubenik 1997). Antler form was tabulated for the entire sample; proportional changes of each form were plotted against age. Similarly, the form of brow palm was tabulated for the entire sample; proportional changes in brow palm were plotted against age. We report the range, mean, and standard deviation (SD) for each variable (i.e., point counts, maximum spread, left and right maxi- mum palm height, left and right maximum palm width, left and right shaft circumference, and distance between the inner most brow points). Paired sample t-tests (P = 0.05) were used to compare the variables from the left and right sides of each set of antlers. Sample sizes for age-specific means are in Table 1. Left and right antlers in moose are gener- ally symmetrical (Solberg and Saether 1993b, Bowyer et al. 2001). Therefore, we arbitrarily chose to plot only the forms and variables for the left antler. Changes in age-specific means ± 1 SD for each variable on the left side of the antlers were plotted to demonstrate changes in antler architectures with age. Correlations between all of the variables were determined in order to show relationships between the various architectural features. Coefficients of Variation (CV) were calculated for each variable to compare variation amongst all variables. RESULTS Age Distribution The mean age of moose was 4.1 ± 2.7 (SD) years (n = 1,686); age ranged from 1.5- 19.5 years (Fig. 5). Since only 2 moose >14.5 years were inspected, we combined the 14.5 (n = 8), 15.5 (n = 1), and 19.5 (n = 1) year old moose into a single >14.5 year old group. Yearling bulls might be under-represented in the sample because of the voluntary require- ment by non-LEH hunters to submit antlers for inspection (Hatter 1999). Antler Form Antler form was recorded for 1,597 sets of antlers; 75% were palmicorn type (67% SP type, 8% FP type) and 25% were cervicorn type (PT). Palmicorn antlers were most com- mon in all age classes except yearlings. The majority of palmicorn antlers in each age class were SP type, whereas <10% in each age class were FP type (Fig. 6). Cervicorn (PT) antlers were the most common type in yearling moose (65%) and decreased in abundance to <10% in moose >3.5 years old. Fig. 4. Morphometrics recorded for moose antlers (Bubenik 1982). M a xi m u m A n tl e r H e ig h t Palm Width 0 50 100 150 200 250 300 350 400 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 14.5+ Age (years) N o. In di vi du al s Fig. 5. Age distribution of hunter-killed bull moose (n = 1,965) from the Omineca sub-region of British Columbia, 1982-1989. ALCES VOL. 46, 2010 CHILD ET AL. – MOOSE ANTLER MORPHOMETRY 127 Brow Palm Form Brow palm form was recorded on 863 left antlers and 811 right antlers of the 1,965 antlers examined; palmation occurred on 13.1% and 12.4% of the left and right sides, respectively. Forked architectures were about twice as common as palmations; 30.8 % (n = 605) on the left and 28.9% (n = 567) on the right side. The remainder was unclassi- fied, being neither forked nor palmated. The frequency of palmated brow palms increased linearly to approximately 25% at 5.5 years, and continued to increase at a slower rate to about 35% at 13.5 years, before decreasing to 10% thereafter. The frequency of forked brows also increased linearly to approximately 45% at 5.5 years, remaining relatively con- stant to 13.5 years, before increasing to 60% thereafter (Fig. 7). Number of Points on Antlers The number of points on the left side Age AF BF NPL MPL BPL MS MHL SCL PWL DIBP 1.5 309 47 360 206 207 306 145 345 221 217 2.5 290 111 346 232 233 323 162 343 249 266 3.5 268 156 312 213 213 295 161 311 238 261 4.5 167 116 197 133 133 190 107 191 152 169 5.5 103 85 122 74 74 118 58 120 80 105 6.5 84 71 94 66 67 92 48 93 78 86 7.5 51 46 70 42 43 70 45 71 53 67 8.5 45 34 49 28 28 47 27 49 41 45 9.5 32 26 34 21 22 33 15 35 26 26 10.5 23 21 26 16 16 24 23 26 20 22 11.5 17 14 18 11 11 17 7 18 14 15 12.5 11 9 12 6 6 11 4 11 7 11 13.5 11 10 11 10 10 11 6 11 10 9 14.5+ 8 7 10 6 6 10 6 10 7 10 Total aged 1419 753 1661 1064 1069 1547 814 1634 1196 1309 Recorded, but not aged 178 110 235 118 119 233 111 251 163 210 Not recorded 368 1102 41 783 777 185 1040 80 606 446 Total Sample 1965 1965 1965 1965 1965 1965 1965 1965 1965 1965 Table 1. Sample sizes for antler form, brow form, and the 8 variables examined on the left antler. AF = antler form, BF = brow form, NPL = number of points on left antler, MPL = main palm points left antler, BPL = brow points left antler, MS = maximum spread, MHL = maximum height left antler, SCL = shaft circumference left antler, PWL = palm width left antler, and DIBP = distance between innermost points on the brow palm. 0% 20% 40% 60% 80% 100% 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 14.5+ Age (years) Pe rc en ta ge (% ) Fig. 6. Changes in antler form with age for hunter- killed moose from the Omineca sub-region of British Columbia, 1982-1989. Note: Black = Pole Type, Dark gray = Split Palm, and Light Gray = Full Palm. MOOSE ANTLER MORPHOMETRY – CHILD ET AL. ALCES VOL. 46, 2010 128 ranged from 0-18, averaging 5.90 ± 2.62 (SD) (n = 1,924; points on the right side ranged from 1-15, averaging 5.81 ± 2.49 (SD) (n = 1,913). There were more points (t = 3.011, df = 1,906, P = 0.003) on the left (mean = 5.90 ± 2.63, n = 1,907) than right side (mean = 5.81 ± 2.49, n = 1907), although the number of points on the left correlated (r = 0.866, n = 1,907, P<0.001) with the number on the right side. Generally, the number of antler points on both sides increased from 1.5-7.5 years, then remained relatively stable there- after (Fig. 8). Number of Points on Main Palms The number of points on the left main palm ranged from 1-13, averaging 4.23 ± 2.01 points (SD) (n = 1,182); similarly, points on the right main palm ranged from 1-14, aver- aging 4.17 ± 1.89 (SD) (n = 1,175). There was no difference (t = 1.797, df = 1,138, P = 0.073) between the numbers of points on the left (mean = 4.24 ± 2.02, n = 1,139) and right main palms (mean = 4.18 ± 1.90, n = 1,139); the number of points on paired left and right main palms were correlated (r = 0.798, n = 1,139, P<0.001). Generally, the number of points on both palms increased from 1.5- 7.5 years, then remained relatively constant thereafter (Fig. 8). Number of Points on Brow Palms The number of points on the left brow palm ranged from 0-7, averaging 1.75 ± 0.88 (SD) (n = 1,188); 0.3% had no measurable points, 46.7% were single points (spikes), 36.4% were 2 points (forks), and 16.7% had >3 points. On the right, points ranged from 0-8, averaging 1.72 ± 0.87 (SD) (n = 1,184); 0.1 % had no measureable points, 48.2% were spikes, 36.5% were forks, and 15.2% had >3 points. There was no difference (t =1.744, df = 1146, P = 0.081) between the number of points on the right (mean = 1.73 ± 0.87, n = 1,147) and left brow palms (mean = 1.76 ± 0.88, n = 1,147); the number of points on the left and right brows were correlated (r = 0.742, n = 1,147, P<0.001). Generally, the number of points on both brow palms increased from 1.5-7.5 years, and remained relatively constant thereafter (Fig. 8). Maximum Spread of Antlers The maximum spread of 1,780 sets of ant- lers ranged from 322-1,613 mm, averaging 858 ± 204 (SD) mm. Maximum spread generally increased annually with age (Fig. 9). Fig. 7. Changes in brow form with age for hunter- killed moose from the Omineca sub-region of British Columbia, 1982-1989. Values are age- specific mean proportion of each type on left antlers. Dashed line is forked brow, solid line is palmated brow. 0 10 20 30 40 50 60 70 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 14.5+ Age (years) Pe rc en ta ge (% ) Fig. 8. Changes in age-specific means of total points, main palm points, and brow points for hunter-killed moose from the Omineca sub- region in British Columbia, 1982-1989. Values are means of the age-specific mean point counts ± 1 SD for the left side. Solid line is total points, dashed line is main palm points, and gray line is brow palm points. 0 2 4 6 8 10 12 14 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 14.5+ Age (years) Po in t C ou nt s ALCES VOL. 46, 2010 CHILD ET AL. – MOOSE ANTLER MORPHOMETRY 129 Maximum Height of Antlers The maximum antler height ranged from 49-1,194 mm. The mean maximum height on the left ( 519 ± 196 mm, n = 925) and right side (mean = 507 ± 192, n = 817) were similar. The maximum height of the left side (mean = 512 ± 188 mm, n =798) was not different (t = 1.858, df = 797, P = 0.063) from the right side (mean = 508 ± 192 mm, n = 798) on each set of paired antlers; the height on the left was positively correlated (r = 0.950, n = 798, P<0.001) with height on the right side. Maximum height of both sides generally increased from 1.5-9.5 years, and remained relatively unchanged thereafter (Fig. 9). Maximum Width of the Main Palm The maximum width of the main palm ranged from 12-436 mm. Palm widths on the left (mean = 163 ± 68 mm, n = 1,359) were similar to those on the right side (mean = 162 ± 66, n = 1,357). The width of the main palm on the left (mean = 163 ± 68 mm) was not dif- ferent (t =1.111, df = 1336, P = 0.267) from the width on the right (mean = 162 ± 66 mm) in paired sets of antlers (n = 1337); width of the main palm on the left was positively cor- related (r = 0.889, n = 1,337, P < 0.001) with width on the right side. Palm width of both sides generally increased with age from 1.5-9.5 years, and declined thereafter (Fig. 9). Circumference of Antler Shaft The shaft circumference of antlers ranged from 55-281 mm. Shaft circumference on the left side (mean = 147 ± 26 mm, n = 1,885) was similar to that on the right (mean = 147 ± 27, n = 1,819). There was no difference (t = 0.596, df = 1,805, P = 0.551) in shaft circumference on the left (mean = 147 ± 26 mm) and right sides (mean = 147 ± 26 mm) for paired sets of antlers (n = 1,806); shaft circumference on the left and right sides were positively correlated (r = 0.913, n = 1,806, P<0.001) for paired sets of antlers. Shaft circumference on both sides slowly increased with age (Fig. 10). Distance between Innermost Points on Brow Palms The distance between the innermost points on the brow ranged from 102-800 mm, averag- ing 375 ± 88 (SD) mm (n = 1,519). Average distance between the brow points narrowed from 417 mm at 1.5 year to 375 mm at 3.5 years. Fig. 9. Changes in age-specific mean values for antler attributes maximum spread, maximum height, and maximum palm width of hunter- killed moose from the Omineca sub-region of British Columbia, 1982-1989. Values are age- specific mean point counts ± 1 SD for the left side. Solid line is maximum spread, dashed line is maximum height of antler, and gray line is maximum width of palm. 0 200 400 600 800 1000 1200 1400 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.514.5+ Age (years) Si ze (m m ) Fig. 10. Changes in age-specific mean values of distance between brow points and shaft circumference for hunter-killed moose from the Omineca sub-region of British Columbia, 1982-1989. Values are age-specific mean point counts ± 1 SD for the left side. Solid line is in- nermost distance between the brow points, and the dashed line is shaft circumference. 0 100 200 300 400 500 600 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 14.5+ Age (years) Si ze (m m ) MOOSE ANTLER MORPHOMETRY – CHILD ET AL. ALCES VOL. 46, 2010 130 This distance remained relatively constant at ~350 mm from 4.5-11.5 years, then widened to >400 mm thereafter (Fig. 10). Correlations between Antler Variables Correlations between each variable on each side of a set of paired antlers (Table 1) were significant (P<0.001). Highest correla- tion coefficients (r) were found for antler height (r = 0.950) and shaft circumference (r = 0.914). Maximum spread, often the measurement of choice by hunters, was highly correlated with all other measures. The dis- tance between innermost points on the brow palms and all other variables had the lowest correlation coefficients. Variability in Antler Measurements The least variable measure was shaft circumference (CV = 18% for both left and right sides); the most variable was number of points on the brow palms (CV = 51% for both left and right sides). Generally, the number of points had most variability (Table 2). DISCUSSION We found that form and morphometrics of antlers of bull moose changed with age in the central interior of British Columbia. These changes progressed through the juve- nile and prime stages, ended in the senior/ senescent stage (Gaillard et al. 2000), and were similar to those described for moose in North America (Timmermann 1971, Bubenik et al. 1978, Van Ballenberghe 1982, Erling et al. 1987, Gasaway et al. 1987). Prime moose (approximately 5-12 years) have near maximal antler size and antler growth plateaus at this stage (Gasaway et al. 1987). Antler size in juveniles (approximately 1-4 years) rapidly increases toward full development, whereas antlers of seniors (>12 years) gradually regress from full development. The mean maximum spread of antlers from our sample was similar to that of A. a. andersoni and A. a. americana, but smaller than that of A. a. gigas (Gasaway et al. 1987). Gasaway et al. (1987) found that both palmicorn and cervicorn (pole type) antler forms occur throughout North America with palmicorn antlers being the predominant form for moose >2 years old; our findings are similar. Furthermore, Bubenik (1997) subdivided palmicorn into full palm (shell type) and split palm (butterfly type) forms; both were documented in the Omineca. Split palm antlers were the most common type in all age classes of moose >2.5 years old, whereas full palm antlers were infrequent in most age classes. We were unable to compare the variation of SP and FP types across North America. The proportion (65%) of yearlings in the Omineca with cervicorn antlers was higher than that documented throughout North America (30-40%; Gasaway et al. 1987). It is unknown whether this higher percentage reflects difference in range condition (Nygrén et al. 2007) and hunting regulations between the Omineca and other jurisdictions, and/or other factors. The pattern of antler architecture and their increasing complexity in design, shape, and size in the central interior of British Co- lumbia was similar to that described in other regions of North America (Timmermann 1971, Bubenik et al. 1978, Gasaway et al. 1987). There was, however, a great deal of variation in antler size and shape among moose of the same age, and between males of different age classes. Given that genetics, location (e.g., range quality), and other factors influence the growth and final design of antlers (Hundert- mark and Bowyer 2004), variation in antler morphometry is not surprising. Knowledge of the age-related growth and development of antlers is important because harvest regula- tions increasingly define “legal” bulls by form and growth characteristics (Child and Aitken 1989, Hatter 1999, Demarchi and Hartwig 2008). It follows then that field collection and measurement of moose antlers is needed to best describe and understand standards, ALCES VOL. 46, 2010 CHILD ET AL. – MOOSE ANTLER MORPHOMETRY 131 N PL N PR M PL M PR B PL B PR M S M H L M H R SC L SC R PW L PW R D IB P N PL -- 0. 86 6 0. 95 3 0. 79 3 0. 71 5 0. 65 1 0. 77 0. 76 4 0. 74 0. 72 1 0. 70 8 0. 80 2 0. 76 -0 .3 51 19 24 19 07 11 82 11 75 11 82 11 78 17 67 91 7 80 9 18 73 18 03 13 51 13 47 15 13 N PR 0. 86 6 -- 0. 80 8 0. 94 7 0. 64 9 0. 71 4 0. 76 7 0. 75 0. 76 2 0. 70 2 0. 72 4 0. 77 3 0. 81 1 -0 .3 61 19 07 19 13 11 70 11 75 11 71 11 75 17 62 91 1 80 7 18 59 18 03 13 40 13 46 15 10 M PL 0. 95 3 0. 80 8 -- 0. 79 8 0. 46 8 0. 50 6 0. 71 9 0. 73 9 0. 70 9 0. 68 8 0. 66 1 0. 76 2 0. 72 3 -0 .2 79 11 82 11 70 11 82 11 39 11 82 11 42 10 93 64 9 61 9 11 71 11 63 10 47 10 41 94 1 M PR 0. 79 3 0. 94 7 0. 79 8 -- 0. 49 4 0. 45 2 0. 69 9 0. 72 0. 74 8 0. 65 2 0. 66 2 0. 74 1 0. 77 8 -0 .3 18 11 75 11 75 11 39 11 75 11 39 11 75 10 94 64 4 61 8 11 62 11 65 10 40 10 45 94 7 B PL 0. 71 5 0. 64 9 0. 46 8 0. 49 4 -- 0. 74 2 0. 56 1 0. 59 5 0. 59 3 0. 55 3 0. 54 0. 60 8 0. 59 3 -0 .4 05 11 82 11 71 11 82 11 39 11 88 11 47 10 97 65 2 62 1 11 77 11 67 10 52 10 45 94 4 B PR 0. 65 1 0. 71 4 0. 50 6 0. 45 2 0. 74 2 -- 0. 57 2 0. 59 6 0. 59 8 0. 56 2 0. 55 9 0. 60 5 0. 60 4 -0 .3 77 11 78 11 75 11 42 11 75 11 47 11 84 11 02 64 8 62 2 11 71 11 73 10 47 10 52 95 3 M S 0. 77 0. 76 7 0. 71 9 0. 69 9 0. 56 1 0. 57 2 -- 0. 80 6 0. 80 5 0. 76 5 0. 76 9 0. 73 0. 72 4 -0 .1 62 17 67 17 62 10 93 10 94 10 97 11 02 17 80 85 5 75 6 17 49 16 86 12 72 12 76 14 98 M H L 0. 76 4 0. 75 0. 73 9 0. 72 0. 59 5 0. 59 6 0. 80 6 -- 0. 95 0. 78 2 0. 78 8 0. 76 2 0. 73 1 -0 .2 71 91 7 91 1 64 9 64 4 65 2 64 8 85 5 92 5 79 8 91 3 90 5 75 3 74 7 75 6 M H R 0. 74 0. 76 2 0. 70 9 0. 74 8 0. 59 3 0. 59 8 0. 80 5 0. 95 -- 0. 75 2 0. 78 0. 77 6 0. 76 -0 .2 6 80 9 80 7 61 9 61 8 62 1 62 2 75 6 79 8 81 7 80 8 80 9 65 8 66 0 66 3 SC L 0. 72 1 0. 70 2 0. 68 8 0. 65 2 0. 55 3 0. 56 2 0. 76 5 0. 78 2 0. 75 2 -- 0. 91 3 0. 69 4 0. 69 2 -0 .2 62 18 73 18 59 11 71 11 62 11 77 11 71 17 49 91 3 80 8 18 85 18 06 13 49 13 40 15 07 SC R 0. 70 8 0. 72 4 0. 66 1 0. 66 1 0. 54 0. 55 9 0. 76 9 0. 78 8 0. 78 0. 91 3 -- 0. 70 1 0. 71 5 -0 .2 59 18 03 18 03 11 63 11 65 11 67 11 73 16 86 90 5 80 9 18 06 18 19 13 39 13 47 14 55 PW L 0. 80 2 0. 77 3 0. 76 2 0. 74 1 0. 60 8 0. 60 5 0. 73 0. 76 2 0. 77 6 0. 69 4 0. 70 1 -- 0. 88 9 -0 .3 14 13 51 13 40 10 47 10 40 10 52 10 47 12 72 75 3 65 8 13 49 13 39 13 59 13 37 10 97 PW R 0. 76 0. 81 1 0. 72 3 0. 77 8 0. 59 3 0. 60 4 0. 72 4 0. 73 1 0. 76 0. 69 2 0. 71 6 0. 88 9 -- -0 .3 06 13 47 13 46 10 41 10 45 10 45 10 52 12 76 74 7 66 0 13 40 13 47 13 37 13 57 11 02 D IB P -0 .3 51 -0 .3 61 -0 .2 79 -0 .3 18 -0 .4 05 -0 .3 77 -0 .1 62 -0 .2 71 -0 .2 6 -0 .2 62 -0 .2 59 -0 .3 14 -0 .3 06 -- 15 13 15 10 94 1 94 7 94 4 95 3 14 98 75 6 66 3 15 07 14 55 10 97 11 02 15 19 Ta bl e 2. P ea rs on c or re la tio n co ef fic ie nt s b et w ee n al l m ea su re m en ts fo r m oo se a nt le rs . A ll co rr el at io ns w er e si gn ifi ca nt a t P <0 .0 01 . S am pl e si ze s a re sh ow n be lo w th e co rr el at io n co ef fic ie nt . N ot e: N PL = n um be r o f p oi nt s o n le ft an tle r, N PR = n um be r o f p oi nt s o n rig ht a nt le r, M PL = m ai n pa lm p oi nt s l ef t a nt le r, M PR = m ai n pa lm p oi nt s r ig ht a nt le r, B PL = b ro w p oi nt s l ef t a nt le r, B PR = b ro w p oi nt s r ig ht a nt le r, M S = m ax im um sp re ad , M H L = m ax im um h ei gh t l ef t a nt le r, M H R = m ax im um h ei gh t r ig ht a nt le r, SC L = sh af t c irc um fe re nc e le ft an tle r, SC R = sh af t c ir- cu m fe re nc e rig ht a nt le r, PW L = pa lm w id th le ft an tle r, PW R = p al m w id th ri gh t a nt le r, an d D IB P = di st an ce b et w ee n in ne rm os t p oi nt s o n th e br ow p al m . MOOSE ANTLER MORPHOMETRY – CHILD ET AL. ALCES VOL. 46, 2010 132 variation, and change amongst managed popu- lations, especially where and if antler-based hunting regulations are planned or practiced (Child et al. 2010). ACKNOWLEDGEMENTS We thank Sean Barry for his meticulous attention to detail in measuring and recording the forms of all inspected antlers and to Ken Fujino and Sean Barry of the Wildlife Branch who prepared and aged the tooth samples. A special thanks to Gerry Kuzyk for release of the antler data records and to the many hunters who willingly submitted the antlers for inspec- tion. We also thank the anonymous reviewers for their comments on an earlier draft of the manuscript. REFERENCES Bowyer, r.T., K. M. STewarT, J. G. Kie, and w. C. GaSaway. 2001. Fluctuating asymmetry in antlers of Alaskan moose: size matters. Journal of Mammalogy 82: 814-824. BuBeniK, a. B. 1973. Hypothesis concern- ing the morphogenesis in moose antlers. Proceedings of the North American Moose Conference and Workshop 9: 195-231. ______. 1982. Proposals for standardized nomenclature for bony appendices in Pecora. Pages 187-194 in R. D. Brown, editor. Antler Development in Cervidae. Caesar Kleberg Wildlife Research Insti- tute, Texas A & I University, Kingsville, Texas, USA. _____. 1997. Evolution, taxonomy and morphophysiology. Pages 77-123 in A. W. Franzmann, and C. C. Schwartz, editors. Ecology and Management of the North American Moose. Smithsonian Institution Press, Washington, D.C., USA. _____, O. williaMS, and H. r. TiMMerMann. 1978. Some characteristics of antlero- genesis in moose: a preliminary report. Proceedings of the North American Moose Conference and Workshop 14: 157-177. BuBeniK, G. a., and P. G. BuBeniK. 2008. Palmated antlers of moose may serve as a parabolic reflector of sounds. Eu- ropean Journal of Wildlife Research 54: 533-535. CHild, K. N. 1982. Moose antlers: how they grow and what they tell you. British Co- lumbia Wildlife Review 10: 17-20. _____. 1992. Moose management in the Omineca Sub-region. Proceedings of the 1991 Moose Harvest Workshop, Kam- loops, British Columbia. Wildlife Branch, British Columbia Environment, Victoria, British Columbia, Canada. _____, and d. a. aiTKen. 1989. Selective harvests, hunters and moose in central British Columbia. Alces 25: 81-97. _____, _____, r.V. rea and, r.a. deMarCHi. 2010. Potential vulnerability of bull moose in central British Columbia to three antler-based hunting regulations. Alces 46: 113-121. CrinGan, a. T. 1955. Studies of moose antler Antler Measurement Coefficient of Variation (%) n Shaft circumference left 18 1885 Shaft circumference right 18 1816 Distance between innermost points on brow palms 23 1519 Maximum spread 24 1780 Maximum height left antler 38 923 Maximum height right antler 38 816 Palm width right antler 41 1355 Palm width left antler 42 1359 Total number points right antler 43 1910 Total number points left antler 44 1921 Main palm points right antler 45 1173 Main palm points left antler 48 1182 Brow points right antler 51 1182 Brow points left antler 51 1188 Table 3. Coefficient of variation for each antler variable. ALCES VOL. 46, 2010 CHILD ET AL. – MOOSE ANTLER MORPHOMETRY 133 development in relation to age. Appendix B in R. L. Peterson, editor. North Ameri- can Moose. University of Toronto Press, Toronto, Canada. deMarCHi, r. a., and C. l. HarTwiG. 2008. Towards an improved moose management strategy for British Columbia. Habitat Conservation Trust Fund Report CAT07- 0-0325. Victoria, British Columbia, Canada. enVironMenT Canada. 2010. Canadian cli- mate normals 1971-2000. (accessed April 2010). enGan, J. H. 2001. Changes in the relation- ship between palmate and cervine antlers in moose (Alces alces) in southeastern Norway. Alces 37: 79-88. erlinG, J., B. e. SaeTHer, d. J. PreSTon, d. J. reed, and d. d. roBy. 1987. Com- parative antler morphology and size of North American Moose. Swedish Wildlife Research Supplement 1: 311-325. Gaillard, J. M., M. FeSTa-BlanCHeT, G. yoC- Coz, a. loiSon, and C. ToiGo. 2000. Tem- poral variation in fitness components and population dynamics of large herbivores. Annual Review Ecology and Systematics 31: 367-393. GaSaway, w. C., d. J. PreSTon, d. J. reed, and d. d. roBy. 1987. Comparative antler morphology and size of North American Moose. Swedish Wildlife Research Supplement 1: 311-325. HaTTer, i. w. 1999. An evaluation of moose harvest management in Central and North- ern British Columbia. Alces 35: 91-103 _____, and K. n. CHild. 1992. An evalu- ation of a spike-fork bull moose antler regulation in central British Columbia. Proceedings of the 1991 Moose Harvest Workshop, Kamloops, British Columbia. Wildlife Branch, Ministry of Environment, Victoria, British Columbia, Canada. HarMel, d. e. 1982. Effects of genetics on antler quality and body size in white-tailed deer. Pages 339-348 in R. D. Brown, editor. Antler Development in Cervidae. Caesar Kleberg Wildlife Research Insti- tute, Texas A & I University, Kingsville, Texas, USA. Heard, d., S. Barry, G. waTTS, and K. CHild. 1997. Fertility of female moose (Alces alces) in relation to age and body com- position. Alces 33: 165-176. HeFFelFinGer, J. 2006. Deer of the Southwest: A Complete Guide to the Natural History, Biology, and Management of Southwest- ern Mule Deer and White-tailed Deer. Texas A&M University Press, College Station, Texas, USA. HiBler, C. P., and J. l. adCoCK. 1971. Elaeo- phorosis. Pages 263-278 in J. W. Davis and R. C. Anderson, editors. Parasitic Diseases of Wild Mammals. Iowa State University Press, Ames, Iowa, USA. HunderTMarK, K., and r. T. Bowyer. 2004. Genetics, evolution, and phylogeography of moose. Alces 40: 103-122. nyGrén, T., J. ruSeniuS, r. TiliKainen, and J. KorPelainen. 2007. Moose antler type polymorphism: age and weight dependent phenotypes and phenotype frequencies in space and time. Annales Zoologici Fennici 44: 445-461. SerGeanT, d. e., and d. H. PiMloTT. 1969. Age determination in moose from sec- tioned incisor teeth. Journal of Wildlife Management 23: 315-321. SolBerG, e. J., and B. e. SaeTHer. 1993a. Male traits as life-history variables: an- nual variation in body mass and antler length in moose (Alces alces). Journal of Mammalogy 75: 1069-1079. _____, and _____. 1993b. Fluctuating asym- metry in the antlers of moose (Alces alces): does it signal male quality? Proceedings: Biological Sciences 254: 251-255. SToneHouSe, B. 1968. Thermoregulatory function of growing antlers. Nature 218: 870-872. TiMMerMann, H. r. 1971. The antlers of MOOSE ANTLER MORPHOMETRY – CHILD ET AL. ALCES VOL. 46, 2010 134 the moose, development related to age. Ontario Fish and Wildlife Review 10: 11-18. ullrey, D. E. 1982. Nutrition and antler development in white-tailed deer. Pages 49-59 in R. D. Brown, editor. Antler Development in Cervidae. Caesar Kleberg Wildlife Research Institute, Texas A & I University, Kingsville, Texas, USA. Van BallenBerGHe, V. 1982. Growth and development of moose antlers in Alaska. Pages 37-48 in R. D. Brown, editor. Antler Development in Cervidae. Caesar Kleberg Wildlife Research Institute, Texas A&I University, Kingsville, Texas, USA. wolF, G. J. 1980. Elk management on a New Mexico ranch. Pages 26-32 in W. Macgregor, editor. Proceedings of the Western States Elk Workshop. British Columbia Fish and Wildlife Branch, Vic- toria, British Columbia, Canada.