Daily ranges and home ranges as determined by GPS dataloggers don’t differ in size in a small central place forager

Animals use home ranges for daily activities such as foraging, mating, and caring for young. Home ranges are often smaller than daily ranges—the areas used within a single day—though the two can be identical, particularly in central place foragers that return to a nest after foraging. Home ranges are measured using GPS collars, but small mammals can only carry light collars with small batteries, restricting data collection. This raises the question whether daily ranges can reliably estimate home range sizes in small mammals. I investigated this in bush Karoo rats, central place foragers living in a seasonal environment. Using mini-GPS dataloggers, I collected high-frequency data (fixes every 5 minutes) over one day to calculate daily ranges, and low-frequency data (fixes every hour) over five days for home ranges. I studied 52 females in the dry season and 61 in the moist season, and 17 males (dry season only, as they are not resident in the moist season). Males had larger home ranges than females but not larger daily ranges. Females showed larger daily than home ranges, especially in the moist season, indicating that frequent fixes in a single day can yield accurate range estimates. Female daily ranges, but not home ranges, were significantly larger in the moist season. These findings suggest that when battery life limits GPS data collection, estimating daily ranges with many fixes may be as reliable—or even more accurate—than estimating home ranges with fewer fixes over multiple days in small central place foragers.