Piscivorous Habit and Echolocation Sound of Myotis ricketti at Fangshan,Beijing

The big-footed bat (Myotis ricketti) is morphologically similar to piscivorous M.vivesi and Noctilio leporinus,but its piscivorous habit leaves a question open.Eighteen of the returning bats were captured with netting at the entrance of their living cave in Fangshan County,Beijing at night.Of 18 stomachs examined,the remains of seven were exclusively fishes (Zacco platypus,Carassius auratus and Phoxinus lagowskii),those of 10 were mainly fish fragments and only one was consisted of insects.In experimental observation,the rate of success in catching fish was 12.5% of 256.The findings indicate that M.ricketti is piscivorous.Echolocation sounds of the bat were frequency-modulated downward from 67.40 to 23.63 kHz with main energy at 38.21±1.18 kHz and short pulse duration of 2.58±0.34 ms.The echolocation sounds are somewhat species-specific.