Effects of Dietary Energy Restriction on the Hunting Behavior and Home-Range Size of Free-Ranging Domestic Cats
Free-ranging cats pose concern for native small mammals and birds due to their reputation as instinctual predators. Hunting and prey consumption may be altered by food amounts received from humans. This study’s objective was to determine the effects of dietary energy restriction on hunting behavior and home-range size of free-ranging cats. Eight free-ranging cats (5 female, 3 male) residing at the Berry College Equine Center were blocked by weight and assigned randomly to receive daily ME requirements for adult cats at maintenance (control; n=4) or 80% of daily ME requirements (restricted; n=4). For 11 months, cats were individually offered commercial cat food daily with additional colored-glitter to identify each cat’s feces. Cats were fitted with harnesses and GPS units to construct home ranges. Feline feces were dried at 60°C and analyzed for prey teeth, total hair, and cat vs. non-cat hair. No differences in BW (P=0.99) or DMI (P=0.66) occurred throughout the experiment. Home ranges were constructed using 95% kernel density estimation and analyzed by season. While no differences in home-range size occurred during spring or summer, fall home-range was larger (P=0.04) for control cats (7.35 hectares; 95% CI 4.72 to 11.43 hectares) compared to restricted cats (3.91 hectares; 95% CI 2.67 to 5.73 hectares). Likewise, winter home-range was larger (P=0.04) for control cats (6.91 hectares; 95% CI 4.71 to 10.12 hectares) compared to restricted cats (3.92 hectares; 95% CI 2.68 to 5.75 hectares). Of 306 fecal samples identified by cat, a similar (P=0.83) percentage of feces from control vs. restricted cats contained hair (92.05% vs. 92.9%). There was a tendency (P=0.11) for total hair weight in control-cat feces (0.55 ± 0.058 g) to be greater than total hair weight in restricted-cat feces (0.42 ± 0.057 g). However, restricted-cat feces had a lower percentage (18.1%; P=0.003) of non-cat hair compared to the percentage (33.1%) of non-cat hair in control-cat feces. The percentage (21.85%) of control-cat feces containing prey bones/teeth was greater (P ˂ 0.0001) compared to the percentage (6.45%) of restricted-cat feces containing prey bones/teeth. However, there was no difference (P=0.82) in total bone/teeth weight for control-cat feces (0.061 ± 0.008 g) compared to restricted-cat feces (0.065 ± 0.015 g). These results suggest that cats will not expand home-range or increase prey consumption when energy-restricted. It may be possible that further restriction of energy intake might affect home-range size and hunting of free-ranging cats.
Keywords: Cats, hunting, energy