Are we to assume that no animal was killed before the fall of the mankind or the concept of death by sin could only be applicable to humans?
I always believed that the first death was the death of the animals that God killed in the Garden of Eden in place of Adam and Eve and used the skin to cover their bodies. The LORD God made garments of skin for Adam and his wife and clothed them (Genesis 3:21). Is that correct?
What about bugs? I find this hard to believe that Adam or Eve didn’t accidentally step on one during their time in Paradise.
Yes. After the fall when Adam and Eve realized that they were naked, God made clothes for them from the skins of animals. I don’t have any idea whether they accidentally stepped on a bug or two. I just know that the Bible says that sin entered into the world through one man and death through sin. To me that says there was no death before Adam and Eve sinned.
The first deaths in the Bible were those of Adam and Eve who were immortal before they sinned and fell to mortality at the moment of their sin. God had told them that on the day they ate of the tree of the knowledge of good and evil they would surely die, and in that sense they did. (Gen. 2:17)
The first actual shedding of blood was in the preparation of clothes for them. God was teaching them that it was by the shedding of innocent blood that they would be covered before him, not by the works of their hands. It symbolized that our righteousness (covering) would be imputed to us by the shedding of innocent blood (the Lord’s) not by our own works.