I know it is back tracking a little, and there is already an "M",
but I just have to include my favourite Haflinger pony's name here,
MUNA, as she was retired to Wales, in January, and I am still heartbroken over her moving so far away.
Nuri wasn't a companion animal in the usual sense of the word. He was a Siberian tiger whom I helped care for at the Washington Park Zoo on weekends back in the 1980s. Nuri was an older guy and hard of hearing, so the senior feline-keeper (whom I assisted) had to blow the "chow's on" whistle loud and long before Nuri would appear in the doorway.
Nuri was a friendly guy who'd rub his face against the bars of his indoor enclosure whenever I was nearby; so when the senior keeper wasn't watching I'd rub Nuri's face — and he loved it! Nuri has long since been in heaven, but I'll always remember him as a dear friend whom it was an honor to know.
Mr. Cat! What a sweetie of a tiger he was, too. I can't believe he used to ask to be petted on the face like a housecat. Did he purr? It must have been fabulous to pet him like that.
Yeah, Nuri was a sweetie and it was great knowing him! No, Panthera cats don't purr, as the relevant bone in their throats doesn't flex the way the relevant cartilage does in Felis cats. However, Panthera cats do have a vocalization for that "bliss" scenario (which sounds like a human's gruff throat-clearing) which is repeated at a lesser frequency than the Felis cats — so it doesn't have the nearly-seamless quality we associate with purring.
Don't know if this counts or not, but I couldn't think of anyone's pet that starts with a U...Ulysses (a dog in one of the V.C. Andrews books that I'm reading).