It's the Chinese Year of the Rat but it is unlikely the animal's status could be elevated above the sewer and loathsome level.

Never mind that last year's hit film Ratatouille showed their humorous - and culinary - side and that Mickey Mouse and Tom and Jerry have been a long-time favorites.

Truth is, according to a Texas A&M University veterinarian, rats are highly intelligent and affectionate animals who have contributed much to medicine.

"Rats are very smart and are known for their problem-solving skills," Dr. Kristina Kalivoda, a rat expert in the College of Veterinary Medicine & Biomedical Sciences, said in a statement. "Many people believe they are filthy creatures. In fact, rats wash themselves several times a day, about as often as most cats."

The difference between a rat and a mouse, Kalivoda explains, is size. Rats are much larger than mice, often three to four times as large, and mice don't live as long as rats.

Rat live up to three years and are prolific breeders, a pair able to produce 15,000 descendants in their lifetime, with females pregnant almost their entire lives.