(20 13? Photographers in Xiamen captured a funny scene of a crow hitchhiking. As the picture shows, the crow actually stood on the back of an eagle in public.

The crow stands on the eagle's back to rest, that is, taking the eagle as a reference. The position of the crow relative to the eagle has not changed, so the crow is still;

When an eagle flies, the air above its wings has a high speed and a low pressure, while the air below its wings has a low speed and a high pressure, so at this time, its wings are subjected to an upward resultant force, thus gaining lift.

So the answer is: eagle; ? It's huge.