Reproduction in mammalian predator and prey : the effects of allometry, phylogeny, and ecology on reproduction in Canidae and Leporidae

Mammalian reproduction is influenced by three factors: allometry (the effect of body size), phylogeny (the effect of ancestral relationships), and ecology (the effect of interactions between organisms and their environment). The relationship between arctic wolf (Canis lupus) pack size and arctic hare (Lepus arcticus) reproduction is well researched; the biomass of available arctic hare prey, an aspect of ecology, is considered the primary factor affecting the size of arctic wolf populations (Mech, 2007). However, Mech (2007) posited that in different regions, the primary factor of predator-prey dynamics might take different forms. The goal of this research was to determine the primary factor, allometry, phylogeny, or ecology, affecting the reproductive patterns of all Canidae and Leporidae in regions across the world rather than in just the arctic. Reproductive variables included litter size, neonatal mass, litter mass, gestation, and lactation. The primary factor of litter size was undetermined. The primary factor of both neonatal mass and litter mass is allometry. The primary factor of gestation appears to be allometry, although phylogeny and ecology also have an effect. Finally, the primary factor of lactation is uncertain; phylogeny and ecology both have an effect. Ecology appears to have a greater impact on species in harsh habitats; the data suggest not only arctic species have distinct reproductive patterns but also desert species. However, ecology has little effect on reproduction in species from less extreme, temperate habitats