This week's selection comes from Richard Ranft, Head of Sound and Vision.
Even among wildlife sound recordists accustomed to capturing unusual sounds, it is a surprise to hear the sound of a rat, and one which literally sings, with a change in pitch and rhythm.
Amazon bamboo rats are a family of large tree rats found in the jungles of south America. While recording forests sounds on an expedition in south-east Peru in 1985, I often heard this sound at night, but didn’t believe locals who claimed it was made by a rat.
I had heard rare recordings in the British Library’s unique sound collections of high-pitched sounds made by the laboratory rat and the widely distributed Brown Rat. But this sound seemed, well, so unrat-like. It was also frustratingly hard for me to record, as whatever creature was making it only vocalised rarely, for a few seconds before going silent, at night in the pitch blackness of the tropical forests, from within dense clumps of bamboo near where I was encamped.
When I finally got this recording after many failed attempts, I was determined to identify the source. So I crept nearer and nearer over a period of about 15 minutes, expecting to see a large frog. Luckily it called again, and I was ready to switch on my torch. There in the light-beam, partly hidden by bamboo stems and leaves, was indeed a furry bamboo rat. Mystery solved! The call is used as a territorial signal to its own kind, much as a bird sings a song in its territory.
Drawing of an Amazon bamboo rat (illustration by Asohn19262 / CC-BY-SA)
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