There is a great many things here that exist that you may not be aware of. Just because you can't see them doesn't mean that they don't exist. Let's take a fan on high speed for instance. The blades are out of your vision. But do they exist? If you doubt slip a finger or two in the fan it's there isn't it? You can't see the air your breathing but it is there keeping you alive. If you were to see everything that is really here you would never go out side. You would just sit in your bedroom under the covers and shake. You might even die of fright.
No. If they existed they would have come up with some better evidence then the measly stuff they have been showing us for years. Especially with the digital equipment and sophisticated tech stuff they have on hand. There would exist tribes of bigfoot creature and a dead one would have turned up.