Duke grew up with his Leona Helmsley/Joan Collins type mother, Millicent. She never threw him the proverbial bone and his understanding of motherly love is rather wan. Not to over analyze him (which his new wife Annika loves to do), but basically Duke gave up on people early in life and found true friendship in his pets, hence his deep connection to animals and his choice to become a vet. His mother can only show affection with money, so she bought Duke his veterinary practice when he graduated. Really, she was just looking for a way to make money and micro-manage his life at the same time. Millicent, incidentally, also showed more love to her pets than to her child. Actually, Duke was born “Bobby” and Millicent legally changed his name after six months to commemorate her pet dog “Duke” that died that year.