Phenotypic variation in past and present Scandinavian wolves (Canis lupus L.)

• Main Author: Engdal, Vilde Arntzen
• Format: Master Thesis
• Language: English
• Published: 2018
• Subjects: Carnivores; Evolution; Ecology; Population differentiation; Norway; Canis lupus
• Online Access: http://hdl.handle.net/10852/67246; http://urn.nb.no/URN:NBN:no-70390

During the last century, the grey wolf (Canis lupus L.) was subject to extensive hunting pressure, which led to functional extinction of this species from the Scandinavian Peninsula around 1970. Wolves reappeared in Scandinavia in 1983 when one male and one female wolf established a territory at the border between southern Sweden and Norway. One new male contributed to the population in 1991, and these three individuals are considered the functional founders of the present wolf population in Scandinavia. The extant wolf population has been subject to numerous studies of pedigree, genetic variability and dispersal. Systematic documentation and studies of morphology have been called for, but are scarce. Also, few studies have investigated morphological differences between the extinct and extant Scandinavian wolf population. Available material from both populations consist of skulls and preserved hides in museum collections. In this thesis, skull measurements and size of foreleg melanin patches were compared between the two populations. Further, standardized photographic documentation and anatomical measures were obtained from recently shot wolves (n=35) during licensed hunts in Scandinavia in 2017 and 2018. This material was used to achieve redundant control for possible confounding factors in the museum material regarding size of melanin markings. The extinct wolf population (museum material, n=12) carried significantly larger foreleg markings than the extant population (n=72) overall. There were no significant effects of sex in either field or museum specimens, but in the field material juveniles had significantly larger melanin patches than adults. Frequencies of males vs juveniles were equally distributed between the extant and extinct fractions of the museum material. The field data further indicated that leg length did not affect the size of foreleg marks. A principal component analysis was performed on 16 craniometric variables obtained from adult males from the extinct (n=11) and extant (n=47) population. Separation of the populations was indicated for the 1st and 3rd PC axis. The most contributing variables to PC1 and PC3 was Condylobasal length (CbL) and forehead slope (Fs), respectively. The study populations significantly differed in both these variables, indicating a longer and flatter skull in extant compared to extinct wolves. Possible explanations for the observed morphological differences could be variation in geographical origin, adaptation to different environments, differences in available nutrients, or simply random founder effects followed by inbreeding. Further research should be carried out in order to understand the genotype-phenotype interaction underlying the differences in morphology between past and present wolves.