Their two heads on the source pic made it irresistible to Photoshop. One looking straight on, the other looking to the side. Two fine eagle head aspects. Both heads can be switched, and reversed. It cannot be left alone. It just can't. This gif has no meaning.
The file is incredibly long at 86 frames, and that's just not done. Nobody does that because it's ridiculous. You can tell a joke in less frames than that.
Extravagantly, luxuriously, wastefully, profligately long.
It's saving grace comes from having a single background. Only the heads move. Each new head must cover the head below it so additional tree is placed around the edges in spots taken from different areas of the background tree.
So the largest portion stays the same throughout and that kept the file size to minimum. But minimum was still at 1.2 MB. So the file was saved at 128 colors instead of 256 colors to bring down the file size. Then optimized by 100% to bring it down further to 451 KB. A considerable savings. A good exchange, file size for quality. This way it loads faster on computers.