Fetal development in wolves, Canis lupus , of the Keewatin District, Northwest Territories, Canada

• Published in: Canadian Journal of Zoology
• Main Authors: Hillis, Tracy L., Mallory, Frank F.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1996
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Northwest Territories; Canada; Canis lupus; inuit; Keewatin
• Online Access: http://dx.doi.org/10.1139/z96-251; http://www.nrcresearchpress.com/doi/pdf/10.1139/z96-251

Of 205 female wolves (Canis lupus) shot by Inuit hunters between 1987 and 1989 in the Keewatin District, Northwest Territories, Canada, 97 were parous, and 16 gravid females carried 73 identifiable fetuses. Fetuses grew at a mean rate of 5.17 g/day between day 32 post coitus and parturition. During the same period, fetuses increased in length at a mean rate of 0.204 cm/day. No significant sexual dimorphism in body mass or other morphological features was found at this stage of development. Cranio-caudal length ranged from 3 mm shortly after implantation to approximately 185 mm at parturition. All correlations of morphological parameters with cranio-caudal length were significant, and with the exception of humerus length and contour length, all parameters increased faster than cranio-caudal length. The results are discussed in relation to reproductive and developmental strategies in canids.