Interesting, this seems to be related to the Bluetooth microphone that they used:
"Thus, we adopted a very small and lightweight microphone placed under the cat’s throat through a collar"
The microphone is described in their paper [0]: "The signal is transmitted via Bluetooth [...] at a sampling frequency of 8 kHz."
Also: "As a consequence, the actual range of frequencies we could rely on is 0–4 kHz. We expected that the fundamental frequency emitted by cats falls within the range, whereas some higher-frequency harmonics were likely to be cut"
I don’t blame them, though, we do it all the time in software development.
My cat will investigate anything pointed at him, and I'm pretty sure would love to see how dead the dead rat really is...
Rather than taking aim at the sampling rate, if anything I'd be more interested in being sure that they'd sampled up to the end of the frequency spectrum that cats can actually hear -- for birds at least the >30kHz part is important.
Or is it intentional? Is there some scientific usefulness that would make these clips easier for a machine to analyze? I really don't know if there would be, since a higher resolution clip could just be sampled again if you really wanted something lower.
It is very unfortunate, but I'm grateful that someone performed this experiment as ethically as they could think of and made the data available for all to use.
https://www.walmart.com/ip/QCY-Mini2-Wireless-Business-Headp...