18th on 21 interesting Facts About Dogs: The average dog is as intelligent as a two-year-old child.
The canine IQ test results are in: Even the average dog has the mental abilities of a 2-year-old child.
The finding is based on a language development test, revealing average dogs can learn 165 words (similar to a 2-year-old child), including signals and gestures, and dogs in the top 20 percent in intelligence can learn 250 words.
Source: http://www.livescience.com/5613-dogs-smart-2-year-kids.html
I really glad to know about these facts. Thanks a lot.