Comparative Behavior of Red and Giant Pandas in the Wolong Reserve, China

Feeding ecology of red pandas ( Ailurus fulgens ) was studied in the Wolong Reserve, China by evaluation of spoor and analysis of nutritional content of bamboo ( Sinarundinaria fangiana ). Radiotelemetry was used to monitor movement and activity patterns of a female red panda. Ecological overlap with the sympatric giant panda ( Ailuropoda melanoleuca ) was extensive in that both species feed primarily on bamboo, but differences in food selection and the abundance and constant nutritional level of bamboo facilitated coexistence. Red pandas subsisted almost exclusively on bamboo leaves whereas giant pandas also ate stems. Dietary overlap was only 40–43% although both species spent approximately 85% of the time in the same area eating the same species of bamboo. Home-range size of the red panda was 3.4 km2 during 9 months, that of a giant panda using the same area at the same time, 6.3 km2. Spatial overlap between the range of the red panda and five radio-collared giant pandas in the area averaged over 70%. Daily linear distances traveled ( x = 481 ± 312 m), percent of the home range used each month (26.6 ± 11.9), and size of core areas (26 ha) were similar for the red panda and one giant panda. Movements of both species were characterized by gradual shifts throughout the home range with certain bamboo areas being visited repeatedly. The red panda was primarily crepuscular and nocturnal, whereas giant pandas were intermittently active day and night. Probability of activity of the red panda (0.37) was significantly lower ( P < 0.001) than that of giant pandas (0.57). The red panda exhibited constant monthly activity levels in contrast to giant pandas that showed significant seasonal variation. Different activity patterns, in spite of similarities in movements and food habits, indicated that the two panda species have different energetic strategies. The red panda has adjusted to a diet low in digestible energy by meticulous selection of individual leaves, extensive mastication, and complex reductions in metabolic rates. By comparison the giant panda is a relatively non-selective feeder that barely chews its food. The energetic and mechanical advantages associated with increased size suggest that the giant panda evolved from a small bamboo-eating animal resembling the red panda.