Consumption rate, food preferences and transit time of captive giant otters Pteronura brasiliensis: Implication for the study of wild populations (original) (raw)

Food consumption, food preferences and transit time of digesta were determined in captive giant otters, Pteronura brasiliensis, at the National Institute of Amazon Research (INPA), Manaus, Brazil. Food consumption of an adult female was 0.0997 kg 1 day 1 . Giant otters showed significant and varied preferences for the single Siluriformes (catfish) and various Characiformes species offered. The adult female preferred Anostomidae and Hypophthalmus (catfish), followed by Triportheus. Myleinae (pacu) were the least preferred, and other species of Characiformes offered were intermediate between Triportheus and Myleinae but not different from one another. The subadult male preferred Psectrogaster, Potamorhina and Semaprochilodus, followed by Hypophthalmus and finally Hemiodontidae. Within species, larger fish are chosen significantly more often than smaller fish (78.7% of trials, P=0.002). Species, size and individual otter significantly affected the percentage of times fish offered were consumed completely (P<0.016). Overall, most fish were consumed completely beginning with the anterior end. Characoids were consumed completely more often than siluroids (77.8% vs. 38.6% of trials, P<0.0001), but the percentage of times different characoids were consumed completely varied (range 0-100%). Small fish (5-15 cm) are more likely to be consumed completely than medium (15-25 cm) fish (84.9% vs. 80.2% of trials, P<0.02). Transit time of particulate markers averaged 3.13 h. Captive preferences are compared to diets of wild otters in the region (central Amazônia), and implications of study results for determination of food habits in wild otters using scat analysis are discussed.