Pets can make a person's life richer, and in the case of these lucky pets, their owners can return the favor long after they are gone. Here's a look at five of the richest pets in the world, including Betty White's dog, Pontiac; Tommaso the cat, who owns three Italian villas; Oprah's dogs; Chihuahua Conchita, who was owned by Gail Posner; and Gene Roddenberry's dogs, whose wealth is out of this world.

Pet: Pontiac

To inherit: $5 million
Owner: Betty White

At 90, actress Betty White is busier than ever. When she's not shooting her TV Land sitcom, "Hot in Cleveland," or promoting her latest memoir, "If You Ask Me (And Of Course You Won't)," you'll find her kicking back at her Los Angeles home with her beloved golden retriever, Pontiac. White has reportedly set up a $5 million trust fund to care for Pontiac and her other pets.

[Photos: Adorable Hotel Lobby Pets]

Pet: Tommaso

Net worth: $13 million
Owner: The late Maria Assunta

This 4-year-old stray alley cat was rescued from the streets of Rome by Maria Assunta, the wealthy, childless widow of an Italian property tycoon. When she died in December 2011, Tommaso inherited her entire estate, including cash and real estate in Rome, Milan and Calabria, Italy.

Oprah's dogs

To inherit: $30 million
Owner: Oprah Winfrey

OK, so the Oprah Winfrey menagerie will have to split the $30 million Oprah promised them several ways. If a dog can't make a go of it on seven figures in a down economy, it's just plain overindulging. 

[Video: Congress is Going to the Dogs]

Pet: Conchita

Net worth: $3 million
Owner: The late Gail Posner

When Miami heiress Gail Posner, wife of corporate takeover king Victor Posner, died in 2010, she left her high-fashion Chihuahua Conchita with a $3 million trust fund and an $8.3 million mansion in Miami Beach, Fla. What suits a hairless heiress most? How about a $15,000 Cartier necklace?

'Star Trek' dogs

Net worth: $4 million
Owner: The late Majel Roddenberry

When Majel Roddenberry, wife of "Star Trek" creator Gene Roddenberry and voice of the USS Enterprise's computer on the hit TV show, died in 2009, she enabled her dogs to boldly go into a tax bracket where few dogs have gone before, thanks to a $4 million trust fund.