Certainly they are far from beeing stupid, but they simply don't have an concept of leaders or hirarchy. You can even train them to do tricks, but it is more difficult as with dogs, not because they are more stupid, but because they must see a reason and have the desire to do it. It's in their nature, in nature it's up to their own strategy and decisions whether they're going to eat or not, there's no herd or a leader that tells them what to do. This is the difference with dogs, nothing to do with intellectual capacity, perfectly equivalent, females are usually somewhat smarter than males, but just as in dogs, there are individual differences, as it also happens with us humans.