Neuroscientist Suzana Herculano-Houzel at Vanderbilt conducted the study in question. In a study that compared not only the brains of dogs and cats but of a wide variety of animals, she found that canines are capable of a higher level of thought than felines. She claims that dogs have 530 million cortical neurons, while cats only have 250 million. This tremendous difference makes canines, on average, significantly more intelligent than cats, and more capable of executing complex tasks.

If you think about it, this makes sense - dogs hold a vast variety of different (and very important) jobs. They serve in the military, protecting the very lives of some soldiers. They assist police officers on the job, sniffing everything out from drugs to explosives. They even help people with disabilities complete tasks that they normally could not do on their own. These are amazing skills that are too challenging for even some human beings.

There are many heart-warming and motivating stories all about dogs that did everything - in some cases, even putting their life on the line - for the good of their owner, or even a stranger. That is a mark of high intelligence in an animal, making dogs the clear winner of any animal IQ test. 

Cats, while having a set of skills that are admirable in their own way, do not complete tasks that are as emotionally and intellectually complex. They are generally too stubborn to assist people with tasks, unlike their canine counterparts. While they do have a personality that is unique and distinctive, they simply don't hold a candle to the smarts of your average dog. 

Don't underestimate your average dog in favor of cats - they are a lot smarter than we give them credit for, and great companions to boot!