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DEVELOPMENT OF BODY MASS AND SEXUAL SIZE DIMORPHISM IN DANISH RED FOXES (VULPES VULPES)
Open accessAbstract
In this study, we examine the development of body mass and sexual size dimorphism (SSD) in 178 juvenile wild Danish red foxes from 99 litters using piecewise analyses of regression lines for age versus weight. When fox cubs are younger than 100 days, only slight (SSD=1.7%) and no significant difference (t-test: t=1.2, p=0.24) was found in the mean weight of males (2.03± kg) and females (1.93± kg), and no significant difference was found in the slope of regression lines for males and females (F=0.97E-5, p = 0.99). In the growth period between 100 days of age and mating around 275 days of age, the regression line in males steepens more than that of females (difference in slopes, F=5.9, p<0.02) and the difference in mean weight of the sexes become highly significant (SSD=7.4%, difference in mean t=4.6, p=2.2E-5). After mating the growth curve levels off i.e. the slope of the regression lines for age versus weight is not significantly different from zero. Yearly variation was revealed in the growth rate of juvenile foxes (difference in slope for males; F=3.9, p<0.01 and females; F=8.6, p<0.001). Conclusion: SSD in red foxes mainly develop as a result of a faster grow rate in males between indepency and maturity. Ontogony of red foxes may genetically be disposed to prevent males outcompeting females in the early stages of life (<100 days), when cubs are still fed by adults and the increase in SSD before mating, may be an adaption to selective forces benefitting larger males. The growth rate of juvenile foxes of both sexes is influenced by environmental variation in different years.
Overview
CoChat Summary
TL;DR
In 178 juvenile wild Danish red foxes from 99 litters, sexual size dimorphism was absent before ~100 days, then developed mainly through faster growth in males between 100 days and mating (~275 days), before growth leveled off. Juvenile growth rates also varied significantly among years.
Key findings
- Cubs younger than 100 days showed no significant sex difference in mean weight: males 2.03±0.1 kg vs females 1.93±0.1 kg, SSD=1.7% (t=1.2, p=0.24), and no significant difference in regression slopes (F=1.97E-5, p=0.99).
- From 100 days to mating (~275 days), males were significantly heavier: 6.3±0.2 kg vs 5.0±0.2 kg, SSD=7.4% (t=4.6, p<2.2E-5); the male age–weight slope was steeper (0.0219 vs 0.0132; F=5.9, p<0.02).
- After mating to one year, mean weights were 6.7±0.2 kg for males and 5.4±0.2 kg for females, SSD=6.9% (t=5.3, p<2.9E-6); slopes were marginally negative and not significantly different from zero (males p<0.41; females p<0.09).
- Growth rate varied by year among juveniles in 1966–1969 (males F=3.9, p<0.01; females F=8.6, p<0.001), and intercepts also differed significantly between years.
Methods
- Mark-recapture data from 178 juvenile wild Danish red foxes from 99 litters, collected 1965–1977; foxes were mainly from Jutland, with some from Zealand and Bornholm, and were weighed when ear-tagged and when recovered dead.
- Age was estimated as days between 1 April of the tagging year and death; analyses used three growth periods: <100 days, 100–275 days, and 275–365 days.
- Piecewise least-squares/GLM regression of age versus weight, t-tests for mean weights, ANCOVA/Pearson tests for slope differences, and yearly comparisons for 1966–1969; SSD was calculated as the percent difference between cube-root mean weights following Cavallini.
Limitations
- Stated: wild cub weights are difficult to obtain; the birth date of Danish red foxes has not been studied, so 1 April was used as a proxy, and variance in birth date may blur the dataset (authors argue this affects both sexes equally and the model is robust because it is based on 99 litters).
- Stated: the main dataset was not normally distributed due to sampling, with cubs mainly caught for earmarking in their first eight weeks and adults mainly recovered after six months; few foxes were recovered in the first six months because the red fox is protected from February to September, and ten recovered dead foxes were removed to prevent bias from illness or decomposition.
- Evident: ages are estimated from an assumed birth date rather than known birth dates; growth period 3 has small samples (15 males, 13 females); yearly variation is analyzed only for 1966–1969, the years with data from at least ten litters.
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In the paper
“and the difference in mean weight of the sexes become highly significant (SSD=7.4%, difference in mean t=4.6, p=2.2E-5).”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
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In the paper
“The intercept of 1967 was significantly lower than the intercept of 1968 (t=2.7, p<0.01)”
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“and no significant difference was found in the slope of regression lines for males and females (F=0.97E-5, p = 0.99).”
- Also stated in: § Results · p. 4 · plain
“Likewise, the slopes of the regression lines for male and female cubs younger than 100 days old did not differ significantly ( F =1.97E-5, p =0.99) (Table 1).”
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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- Also stated in: § Results · p. 4 · plain
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In the paper
“Also, the slope and intercept of the regression lines for 1968 and 1969 differed significantly (F = 9.7 p < 0.01, F = 1.6, p = 0.11, t = 3.2, p < 0.002)”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For juvenile females, the slope of the regression line for age versus weight was significantly steeper in 1966 than in all other years (1967; F=18.6, p<0.001, 1968; F=35.7, p<3.4E-7, 1969; F=8.7, p< 0.01)”
plainstates an association- Asserted: passes — The authors put it forward as true.
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Percentages, sums and reported differences re-computed from the paper’s own numbers.
Each contradiction between two passages listed here was confirmed by an independent check.
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ 3. From sexual maturity (275 days) to one year of age. · p. 4
“SSD was calculated as the percent difference between the cube root of the mean weight of males and females following Cavallini, (1995).”
§ Results · p. 4
“SSD = % of difference between the square root in body mass of males and females.”
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Birth date and individual litter size · p. 7
“100 days 10 June”
§ Birth date and individual litter size · p. 7
“Considering 1 st April to be the birth date of cubs”
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Yearly variation in the body size of juvenile foxes · p. 6
“1967; t =18.6, p=0.05”
§ Yearly variation in the body size of juvenile foxes · p. 6
“| 1967 | F = 1.5 , p < 0.47 t = 2.0, p = 0.05 F = 1.9, p < 0.13 |”
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Results · p. 4
“males (n=96) and 1.93±0.1S.E. kg for females (n=71)”
§ Results · p. 4
“| N | 97 | 69 | | 37 | 28 | | 15 | 13 | |”
Citations
Cites
American Journal of Physical Anthropology
(2006) · American Journal of Physical Anthropology · doi:10.1002/(issn)1096-8644 · Cited by 2,700
Fairbairn, D. J. (1997) · Annual Review of Ecology and Systematics · doi:10.1146/annurev.ecolsys.28.1.659 · Cited by 1,036
Social organization of the spotted hyaena Crocuta crocuta. II. Dominance and reproduction
Frank, L. G. (1986) · Animal Behaviour · doi:10.1016/s0003-3472(86)80221-4 · Cited by 358
Fairbairn, D. J. (2005) · The American Naturalist · doi:10.1086/444600 · Cited by 207
Early development, adult mass, and reproductive success in bighorn sheep
Festa-Bianchet, M., Jorgenson, J. T., & Réale, D. (2000) · Behavioral Ecology · doi:10.1093/beheco/11.6.633 · Cited by 177
Maternal Investment and Neonatal Growth in Phocid Seals
Kovacs, K. M., & Lavigne, D. M. (1986) · Journal of Animal Ecology · doi:10.2307/4432 · Cited by 165
An Analysis of Some of the Factors Affecting Dispersal in an Urban Fox (Vulpes vulpes) Population
Harris, S., & Trewhella, W. J. (1988) · The Journal of Applied Ecology · doi:10.2307/2403833 · Cited by 165
The development of sexual dimorphism: seasonal and lifetime mass changes in bighorn sheep
Festa‐Bianchet, M., King, W. J., Jorgenson, J. T., Smith, K. G., & Wishart, W. D. (1996) · Canadian Journal of Zoology · doi:10.1139/z96-041 · Cited by 156
Resource partitioning among British and Irish mustelids
McDonald, R. A. (2002) · Journal of Animal Ecology · doi:10.1046/j.1365-2656.2002.00588.x · Cited by 154
Kidawa, D., & Kowalczyk, R. (2011) · Acta Theriologica · doi:10.1007/s13364-011-0031-3 · Cited by 119
Research works printed but not linked: 6
- Iossa G. Soulsbury CD. Baker PJ. Harris S 2008. Body Mass, Territory Size, and Life-History Tactics in a Socially Monogamous Canid, the Red Fox Vulpes vulpes . Journal of Mammalogy, 89, 1481-1490.
- Jensen B 1973. Movements of the Red Fox ( Vulpes vulpes L . ) in Denmark Investigated by Marking and Recovery. Danis Review of Game Biology, 8, 1-20.
- Kilanowski AL. Kilanowski AL. Koprowski JL 2016. Female-biased sexual size dimorphism: ontogeny, seasonality, and fecundity of the cliff chipmunk (Tamias dorsalis). Journal of Mammalogy, 98, (1), 204-210.
- Lindström E 1983. Condition and growth of red foxes ( Vulpes vulpes )in relation to food supply. Journal of Zoology, 199, 117-122.
- Macdonald DW. Courteney O 1996. zorros, Cerdocyon thous , in Amazonian Brazil (Carnivora, Canidae), Journal of zoology,
- Swanson EM. McElhinny TL. Dworkin I. Weldele ML. Glickman SE. Holekamp KE. 2013. Ontogeny of sexual size dimorphism in the spotted hyena ( Crocuta crocuta ). Journal of Mammalogy, 94, 1298-1310.
Cited by
(EFSA), E. F. S. A., Díez‐León, M., Dippel, S., Edwards, S., Schwarzer, A., Candiani, D. F., Hempen, M., Lima, E., Caravaca, C. M., Tirchett, N. J., et al. (2025) · EFSA Supporting Publications · doi:10.2903/sp.efsa.2025.en-9562 · Cited by 3
Metadata
- Authors
- Pagh, S., Mariann, C., B, J., Cino, P., & Mette Sif, H.
- Affiliations
- Aalborg University (DK)
- ORCID
- Pagh, Sussie
- Venue
- GABJ
- Publisher
- University of Tlemcen
- Published
- 2018-01-25
- Volume
- 2
- Issue
- 1
- Pages
- 32-43
- ISSN
- 2588-185X (ISSN-L)
- 2602-5582
- OpenAlex
- W4247841832
- Cited by
- 1
- References
- 34
- Citations by year
- 2025: 1
- FWCI
- 0.00
- Type
- journal article
- Language
- en
- Open access
- diamond
- doi.org
- Licence
- Locations
- Genetics and Biodiversity Journal (publishedVersion, cc-by-nc)
- VBN Forskningsportal (Aalborg Universitet) (publishedVersion, cc-by)
- Funders
- 15. Juni Fonden
- Topics
- Life Sciences › Agricultural and Biological Sciences › Ecology, Evolution, Behavior and Systematics › Animal Behavior and Reproduction
- Life Sciences › Agricultural and Biological Sciences › Ecology, Evolution, Behavior and Systematics › Morphological variations and asymmetry
- Physical Sciences › Environmental Science › Ecology › Wildlife Ecology and Conservation
- Keywords
- red fox, sexual size dimorphism, body mass, juvenile growth, ontogeny, growth rate, sexual maturity, interannual variability, sex differences in growth
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- CoChat. (2026). Citation check: DEVELOPMENT OF BODY MASS AND SEXUAL SIZE DIMORPHISM IN DANISH RED FOXES (VULPES VULPES). https://app.cochat.ai/papers/10.46325/gabj.v2i1.112
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- Pagh, S., Mariann, C., B, J., Cino, P., & Mette Sif, H. (2018). DEVELOPMENT OF BODY MASS AND SEXUAL SIZE DIMORPHISM IN DANISH RED FOXES (VULPES VULPES). GABJ. https://doi.org/10.46325/gabj.v2i1.112
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