Purring is often believed to indicate a positive emotional state, but cats sometimes purr when they are ill, tense, or experiencing traumatic or painful moments.
en.wikipedia.org It was here that she developed her trademark sultry purr having decided to compete with the noisy crowd with subtlety rather than volume.
en.wikipedia.org When at play or traveling, they sometimes give off low, purring grunts.
en.wikipedia.org In the first season of the series, after she says her lines, she tends to meow, purr and screech, just like a real cat.
en.wikipedia.org They produce the usual range of sounds for cats, including growling, hissing, purring, and calling.
en.wikipedia.org