Screened on the BBC last month, Horizon: The Secret Life of the Cat, and a follow up show Little Cat Diaries, provided an entertaining, revealing and really rather cute insight into what Tiddles and his friends get up to after they disappear through the catflap. But recording the miaowing and hissing of puss on patrol required nothing more than a cheap off-the-shelf microphone, it transpires.
The chocolate-box village of Shamley Green in Surrey was the location for the experiment jointly conducted by a couple of renowned cat scientists – yes, there are some – working alongside the Royal Veterinary College and the BBC R&D department. Fifty felines were fitted with GPS tag collars and tracked through the night by a team at ‘Cat HQ’ (the village hall) as they roamed the village, burglarised Whiskas from feeding bowls in neighbours’ houses, raided birds’ nests and – well – generally tried to avoid each other. They are solitary creatures, after all.
After the initial GPS observations, several of the cats were fitted with specially customized ‘catcams’, so that the movements of the moggies could be filmed and analysed for the Horizon programmes.
Creating a workable design for the catcam that could provide video and audio footage of broadcastable quality over a period of several hours took a considerable amount of experimentation, testing and customization. (BBC technologist Alia Sheikh has written an excellent blog piece if you want the full details.)
In short, the R&D team repurposed an off-the-shelf £40 HD808 keyring – or ‘spy’ – camera for the job, giving it a firmware update, upping the bitrate, disabling components that might drain the battery and so on. The finished working version was able to produce around two hours of footage per cat per night, storing it on a mini-SD card which could then be transferred to post-production editing tools at Cat HQ.
In the televised programme, the patrolling cats can be heard purring, miaowing and producing other catty noises on their nocturnal adventures. However, assistant producer Alex Ranken (who also took the photos of Kato, top, and Rosie) told PSNEurope that no specialist microphones were used to record these sounds.
“Sorry to disappoint you!” he said, “But we just used the HD808 built-in mic. Even in the plastic catcam housing, it was good for picking up sound up to a couple of metres away. And of course, because they were under the animals’ chins, they captured all the noises that each cat made too, when they were fighting or stalking or whatever.”
The catcam microphones aided the documentary makers in an unexpected way, though. “Because of all the filming at night, sometimes the video footage couldn’t capture exactly what was going on,” reveals Ranken. “However, using the audio, that helped to inform the researchers.” If the cat hissed, for instance, the team knew another cat was in the vicinity, and they could look for signs of enemy eyes in the dark.
The first show, the Secret Life of Cats was watched by nearly five million people – almost treble the BBC2 Horizon average of 1.7 million. Ranken told PSNEurope that in total, the catcam footage revealed that out of the 35 homeowners who participated in the study, 11 of their catflaps were breached by pets other than their own.
In a happy corollary to the second documentary, Little Cat Diaries, a nameless black-and-white interloper spotted on a food raid has finally been claimed, Ranken said. The stray had gone AWOL a year before from a neighbouring village and the owner recognised the missing moggy when the Horizon shows were aired.
At the time of writing, both documentaries were still available on BBC iPlayer.