2008 NORTHEASTERN NATURALIST 15(2):303–308 Pelage Spotting and Staining in Eastern Moles (Scalopus aquaticus) Ava A. Kamm1, George A. Feldhamer1,*, and John D. Reeve1 Abstract - We quantified relative extent of pelage staining in Scalopus aquaticus (eastern mole) as an indicator of scent-gland marking, and evaluated whether staining was associated with colored pelage spots and patches often prevalent on the snout and ventral surface of individuals. Moles were collected from southern Illinois (n = 91) and from Cincinnati, OH (n = 152). Adult moles scent-marked more than juveniles, but pelage staining was independent of breeding season for males and females. Pelage spotting occurred in 33.7% of the sample and was not associated with pelage staining from glandular secretions, as has been suggested by some previous investigators. Pelage spots were most prevalent on the ventral surface. Ventral spotting occurred more often in males than females (P < 0.001). Mean area of ventral spots was 2.81 cm2 with no differences in area related to sex or age. Introduction Like many other talpids, Scalopus aquaticus Linnaeus (eastern moles) rarely are studied and are difficult to observe directly because they live underground. Adults generally are solitary except during the breeding season. Home ranges may overlap, although more than one animal rarely is found in a tunnel system (Harvey 1976). Olfactory communication is more effective for moles than visual or auditory signaling (Gorman and Stone 1990). Moles use urine and anal secretions at distinct sites throughout their area where such marking is most likely to be encountered to alert conspecifics that an area is occupied. The abdominal fur of moles often is stained brown from glandular secretions. In addition to direct marking with urine, preputial secretions also are deposited in tunnels of Talpa europaea Linnaeus (European moles) as they move (Gorman and Stone 1990). Pelage of the eastern mole is short and velvety; it is gray in the northern part of the range and brown or tan in the southern and western part (Whitaker 1996). Orange, yellow, or olive tints on the chin and other parts of the pelage occur in eastern moles and many other North American species (Cockrum and Meinkoth 1942, Hartman and Yates 2003, Miller 1921). Colored fur often occurs where sudoriferous glands are abundant such as the dorsal snout, chin, breast, abdomen, wrists, and the perineal region. Eadie (1954) reported that the orange spots were a product of the sudoriferous and perineal glands, and that spotting was more pronounced in males during the breeding season. Conversely, Jackson (1915) and Carraway and Verts (1991) believed that pelage spotting in moles was a genetic factor. Our objectives were to determine if age, gender, breeding season, body mass, pregnancy, or location affect the presence 1Department of Zoology, Southern Illinois University, Carbondale, IL 62901-6501. *Corresponding author - feldhamer@zoology.siu.edu. 304 Northeastern Naturalist Vol. 15, No. 2 and intensity of pelage staining and spotting in eastern moles, and to determine if pelage staining affects the presence and intensity of pelage spotting. Methods and Materials Data collection Eastern moles were collected from southern Illinois (approximately 37.72°N, 89.20°W) and the Cincinnati, OH (39.16°N, 84.46°W) area from October 2004 until May 2005. All specimens were collected with kill traps (Victor® mole traps) primarily by professional mole trappers at both locales. All specimens were stored at about 10 °C until postmortem examinations were conducted. Specimens were weighed to the nearest gram on a Hanson Dietetic Scale Model 144. Total length, tail length, and hind-foot length were recorded, and skulls were removed and cleaned using dermestid beetle larvae. The reproductive tracts of females and the testes of males were removed and weighed to the nearest 0.01 g on a Denver Instrument Digital Scale to help assess the reproductive status of individuals. In addition, females were categorized either as pregnant or not pregnant by visual inspection of the uterus and ovaries. Sex, date and location of collection, and age were recorded for each specimen, although sex could not be determined for all specimens. Yearly age classes from juvenile through 5 years were determined based on wear criteria of the upper cheek teeth (Hartman 1995) of cleaned skulls. We classified juveniles as “young” (those collected April through June and that likely were within their natal area), or “old” (collected July through December and dispersed from their natal area) based on reproductive data, tooth-wear characteristics of the last upper molar, and date of capture. We assessed two aspects of pelage color variation in eastern moles. The brown wash that often appears on the mid-ventral line, snout, and chin of animals caused by glandular secretions we termed “pelage staining.” The distinct patches of fur primarily on the venter (Fig. 1) and snout that range in color from white to bright orange we considered “pelage spotting.” Pelage spotting and staining were quantified using a Munsell Color Chart based on the intensity of color. To quantify staining, the hue, value, and chroma (Munsell Color 1975) were combined into one of three categories: strong (= 2), light (= 1), or none (= 0). A pelage stain value from 0 to 2 was assigned to each area on the body where staining occurred—snout, chin, chest, and genitals. Ventral staining results in a different color than the flanks and the dorsum of the animal. If the midline staining was ≥3 Munsell values different than the flanks and dorsum, the staining was considered “strong.” If the staining was 2 chroma values different than the flanks and dorsum, the staining was considered “light.” If the midline was the same color as the flanks and the dorsum, the animal was considered to have no staining. Pelage staining values from the snout, chin, chest, and genital areas were combined to form a score between 0 and 8. Pelage spotting could also occur on the snout, chin, or chest, occasionally extending to the genitals of an individual. Pelage spotting was categorized as “strong” if the Munsell value was yellow-orange to brown-orange and was 2008 A.A. Kamm, G.A. Feldhamer, and J.D. Reeve 305 coded as 2 for analyses, “light” if the value appeared yellow or beige (code = 1), and “no color” if the fur appeared white (code = 0). Individuals with no spotting were coded as -1. Statistical analyses SAS 9.1 for Windows (SAS Institute, Inc., Cary, NC) was used for statistical analyses. General linear models were used to test the effect of independent variables (sex, season, body mass, age, location, and pregnancy) on the dependent variable total pelage staining. A general linear model was also used to test the effect of the independent variables sex, season, body mass, age, location, and pelage staining on the presence or absence and color intensity of pelage spotting. Season was considered as pre-breeding (October, November, and December), breeding (January, February, March, April, and May) and post-breeding (June, July, August, and September). Age was recorded as juvenile (individuals less than 1 year of age) or adult (individuals ≥1 year of age). Location either was Illinois or Ohio. General linear models were constructed with males and females combined and the variable “pregnancy” excluded. After conducting this initial test, it was determined that sex had no significant effect on pelage staining, but did have a significant effect on pelage spotting. Thus, the general linear models for pelage staining were conducted again, separating males and females to include the independent variable pregnancy in the females’ model. To reduce the number of variables in the general linear models, those that had P > 0.25 were eliminated. Variables with P ≤ 0.25 then were tested for significant interactions. Interactions with P > 0.05 were not included in the final model. The adjusted Least Squares Means were calculated for each significant variable in the model, and the Tukey-Kramer method was used to test for significant differences between the adjusted means for each group found significant. The upper and lower 95% confidence intervals for each Figure 1. Large orange pelage spot on the venter of an eastern mole. 306 Northeastern Naturalist Vol. 15, No. 2 adjusted mean also were calculated. Data were not transformed because residuals were normally distributed. Results A total of 243 moles was collected. We collected 91 individuals from southern Illinois (19 juvenile males, 34 adult males, 13 juvenile females, and 25 adult females) and 152 moles from Cincinnati, OH (24 juvenile males, 39 adult males, 25 juvenile females, and 64 adult females). Mean mass of testes peaked in February (mean = 1.16 g ± 0.10), consistent with anticipated peak breeding based on latitude (Gorman and Stone 1990). We found most adult females were pregnant in March. Pelage stains For males, age had a significant effect on pelage staining (P < 0.0001), with adults having more staining than juveniles (Table 1). The adjusted mean value for staining in adults was 6.7 ± 0.9, whereas that for juveniles was 2.8 ± 1.3. The general linear model explained 61% of the variation in male pelage staining. Adult females had more pelage staining (P < 0.0003) than did juvenile females (Table 1); the adjusted mean staining was 4.9 ± 0.7 for adults and 2.5 ± 1.3 for juveniles. In contrast to our findings for males, the general linear model for females explained only 17% of the variation. The month of capture was known for 70 of our 81 juveniles. “Young” juveniles (n = 50) had a significantly lower mean staining value (mean = 0.70 ± 0.33) than “old” juveniles (n = 20; mean = 3.85 ± 0.53; t = 5.04, P less than 0.0001). Pelage spots Of 243 moles, 82 (33.7%) had pelage spots in one or more areas. Spotting occurred on the snout and chin, and rarely on the wrist or top of the head. Spotting usually was orange and was most pronounced on the chest and abdomen. A single contiguous chest/abdominal spot occurred in 45 individuals, whereas 8 others had two to four separate ventral spots. The mean area of ventral spotting was 2.81 cm2 (SD = 4.65) and ranged from 0.04 to 25.0 cm2. There was no difference in the mean area of ventral spots between males (3.22 cm2) and females (1.59 cm2) (F = 1.31, d.f. = 49, P = 0.26). Likewise, there was no relationship between the area of ventral spots and age (F = 0.354, R2 = 0.009). Given the Table 1. Variables affecting pelage staining in Scalopus aquaticus (eastern mole) collected in southern Illinois and Cincinnati, OH from 2004 to 2005. Source of variation d.f. F-value P-value Males Season 2 1.67 0.20 Body mass 1 3.66 0.06 Age 1 21.92 less than 0.0001 Location 1 2.66 0.11 Age x season 2 0.90 0.41 Age x location 1 3.21 0.08 Females Age 1 13.69 0.0003 Pregnancy 1 3.65 0.06 2008 A.A. Kamm, G.A. Feldhamer, and J.D. Reeve 307 observed sex ratio of our sample for specimens where sex was determined (1M:1.11F), we found significantly more males (n = 36) with ventral pelage spots than females (n = 15; χ2 = 11.75, d.f. = 49, P < 0.001). None of the variables in the general linear model for pelage spotting was significant (Table 2), and the model explained only 0.05% of the variation in the data. Discussion Pelage stains The primary factor that affected pelage staining in males and females was age; adults had significantly more staining than juveniles. Juveniles, especially those that were captured during the first 6 months of the year, likely would not have left their natal territories yet and would not need to scentmark to establish their own territories. Eadie (1954) found that juveniles had no anal gland staining until 4 months after birth. This is consistent with differences we found in juveniles depending on whether they were collected earlier or later in the year. Nonetheless, the adult female model had very little explanatory power. Thus, factors investigated in this study did little to explain what variables affect scent-marking in females. Surprisingly, staining was not significantly affected by season. This suggests that the frequency that eastern moles scent-mark is the same regardless of the season. If there is an increase in scent-marking during the breeding season, we did not detect it based on pelage staining. Although the composition of glandular secretions differs during the breeding season, at least in European moles (Khazanehdari et al. 1996), the amount of scent-marking by eastern moles throughout the year may consistently display territorial information. Similar to Eadie (1954), we found that adults had more pelage staining than juveniles. Conversely, he found that males had more staining than females, and that adults had more staining in the breeding season than at other times of the year. His findings may have been biased by his methods. He graded the areas of staining as “strong,” “light,” “trace,” or “none” for each specimen and designated arbitrary values on a numbered scale of 1–10 for those 4 grades. Furthermore, Eadie did not use a color chart to measure the levels of staining, nor did he include staining of the genital area in his study; he also considered orange pelage spots as staining. Pelage spots The general linear model results for pelage spotting only explained 0.05% of the variation in the data. Therefore, the model had no biological significance Table 2. General linear model for effects of pelage stains on pelage spots in Scalopus aquaticus (eastern moles) collected 2004–2005. Both sexes were combined. Source of variation d.f. F-value P-value Staining 1 0.17 0.68 Sex 1 3.15 0.08 Season 2 1.30 0.27 Body mass 1 0.21 0.65 Age 1 0.20 0.66 308 Northeastern Naturalist Vol. 15, No. 2 in terms of factors investigated in our study. Carraway and Verts (1991) also found an absence of seasonality in the color intensity or presence of pelage spots in Scapanus townsendii Bachman (Townsend’s mole). As would be expected if spotting was a genetic trait, we found age or glandular staining had no effect on spotting. We conclude, as did Carraway and Verts (1991), that pelage spotting was not due to glandular secretions but is genetically controlled. Hartman and Yates (2003) noted that yellow, orange, or olive pelage spotting is a widespread phenomenon in several genera of North American moles in addition to Scalopus, including Condylura, Parascalops, and Scapanus. It is difficult to ascribe any adaptive significance to brightly colored ventral pelage in a subterranean species such as the eastern mole. Nonetheless, such coloration must not reduce personal fitness either, given its common occurrence within and among populations of eastern moles and other talpids. Acknowledgments A previous draft of the manuscript benefited from the input of L.N. Carraway and an anonymous reviewer. We thank local mole trappers for supplying most of the specimens for this research. We especially thank Greg Hartman for his insight on age determination of moles and editorial assistance on the manuscript. Karen Jones, Department of Animal Science, provided helpful insight throughout this study. Support was provided through the Department of Zoology, Southern Illinois University. Literature Cited Carraway, L.N., and B.J. Verts. 1991. Pattern and color aberrations in pelages of Scapanus townsendii. Northwest Science 65:16–21. Cockrum, E.L., and N.A. Meinkoth. 1942. Abnormal coloration in the prairie mole. Journal of Mammalogy 23:451. Eadie, W.R. 1954. Skin gland activity and pelage descriptions in moles. Journal of Mammalogy 35:186–196. Gorman, M.L., and R.D. Stone. 1990. The Natural History of Moles. Cornell University Press, Ithaca, NY. 138 pp. Hartman, G.D. 1995. 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