We're always learning more about man's best friend, in particular how our relationships with dogs both help us and hurt them. Here, a roundup of this year's most remarkable research findings about canines:

1. Dogs imitate their owners
Dogs mimic some of their owners' body movements, gestures, and other behaviors as part of a phenomenon called "automatic imitation," according to a new study published in the latest Proceedings of the Royal Society B. As part of the study, the researchers asked humans to open a sliding door using alternatively their hands or their heads (more proof that people will do anything for their pets?). Their dogs consistently followed suit, using their paws or heads, even if the mimicry was not rewarded with a food treat. 

2. Dogs can have OCD
Like people, canines are susceptible to mental illness. In the January issue of Molecular Psychiatry, scientists report that they've identified a gene tied to obsessive-compulsive disorder in certain breeds such as Dobermans and bull terriers. Behaviors that once seemed merely curiously doggy like tail-chasing or blanket sucking may, say researchers, be linked to OCD. This research could lead to "treatment or prevention of compulsive disorders in at-risk canines and humans," says Dr. Edward Ginns of the University of Massachusetts, one of the researchers. (Test your dog for OCD)

3. They (probably) come from the Middle East
French poodles and German shepherds notwithstanding, new archaeological evidence "closely links the domestication of dogs in the Middle East with the rise of human civilization there," scientists say in a March issue of Nature. Previous research placed dogs' first origins in East Asia, but new findings — including skeletal remains of dogs buried beside humans — point to areas in modern-day Iraq, Syria, Lebanon, and Jordan where other animals and agriculture developed. "Way beyond falafel, coffee, and meat on a spit, modern humanity has a lot to thank the region for," says Dennis Romero at L.A. Weekly.

4. We've destroyed dogs' ability to think for themselves...
Generations of dogs who've grown up in cozy suburban homes have lost much of the savvy their ancestors had in the wild," says a study in Animal Behaviour. In intelligence tests, wolves wildly outperform pet dogs on "any problem-solving tasks that are non-social," says lead researcher Bradley Smith of the University of South Australia. Domesticated dogs have become so dependent on their owners that they will bark for help rather than fend for themselves, says the research, becoming "puzzled and confused."

5. ...and we're making them fat
An estimated 35 percent of dogs are overweight — and pet owners who struggle with their own weight tend to have pudgier dogs, says a Dutch study published in Public Health Nutrition. This pattern does not, intriguingly, extend to cats, who handle their own exercise regime. "[S]core one for cats," says Maria Goodavage at Dogster.com. "Their stereotypical independence from their humans may prove a healthy habit after all."