Paul & Jane with their Old English sheepdog Martha ! Born on June 16, 1966, Martha inspired the song "Martha my dear" on the White Album. Paul said this about his beloved pet :

“She was a dear pet of mine. I remember John (Lennon) being amazed to see me being so loving to an animal.”  He said, ‘I’ve never seen you like that before.’ I’ve since thought, you know, he wouldn’t have.  It’s only when you’re cuddling around with a dog that you’re in that mode, and she was a very cuddly dog.”

Martha died in 1981, aged 15. Paul bought another sheepdog after that and named her Arrow. She is featured on the cover of Paul's 1993 album "Paul is Live". Info from FeelingNumb & scan by me.