The fine structure of home ranges of male Chelydra serpentina: are snapping turtles territorial?

Four male snapping turtles (Chelydra serpentina) were located by radiotelemetry during the summers of 1985 and 1986 in 5.5-ha Broadwing Lake, Algonquin Park, Ontario. We measured sizes and overlaps of home ranges and core areas. Average size of home range did not differ greatly between years, and location of individual home ranges remained stable from one year to the next in two of three turtles studied both years. Within individual home ranges, the distribution of locations of most turtles was aggregated, but was not significantly different from Poisson distributions. Home ranges overlapped, but the proportion of areas used intensively by individuals was not different in overlapping and nonoverlapping areas, indicating that the areas of intensive use were not exclusive. However, the turtles spaced themselves farther apart than expected from the geometry of the home ranges, possibly the result of intraspecific aggression. If territory is defined as a fixed, exclusive, defended area, then male snapping turtles are not territorial during the summer, but occupy relatively stable home ranges which overlap, and whose spacing may in part be determined by aggressive interactions.