Hi Peggy,
As others have shared, the verse in Rev. 6:8 tells about 4 judgments and one is the beasts of the earth.
 
I'd like to point out that God also lists these four judgments in the Tenach (Old Testament) that He will bring upon man for disobedience.
 
Lev. 26:22   "I will also send wild beasts among you, which shall rob you of your children and destroy your cattle, and make you few in number..."     Then in verses 25, 26 the other 3 judgments of Rev. 6:8 are listed.
 
Ezekiel 5:17  "So will I send upon you famine and evil beasts, and they shall bereave thee; and pestilence and blood shall pass through thee; and I will bring the sword upon thee, I YHVH have spoken it."
 
Ezekiel 14:21  "For thus saith the Lord YHVH; How much more when I send my four sore judgments upon Jerusalem, the sword and the famine, and the noisome beast and the pestilence to cut off from it man and beast?"
 
So it seems these are four main judgments that YHVH brings upon mankind for their disobedience to Him.    The one about the beasts would certainly explain the actions of the animals as you describe.
 
Shalom,
 
Roberta.