Glad you mentioned seals. I have to do one on a back door. I have copperheads and one could easily slither under the door. BUT the worst happened last week. I have a "snake" dog, Dinah Shore. I heard her and thought she was in the front, so I ran out front door. She was in the back and thinking it was a copperhead that I could dispatch with one good hit, I didn't pick my big shovel up. My trimmer broke and I have some 'wandering jew' that grew up between the rocks on the back patio. I looked for a copperhead and all at once realized I was looking at the open mouth of a cottonmouth water moccasin! It took forever to 'kill' it. I carried it on a stick and put it in a wastebasket on a garden table. I heard Dinah again and ran back outside and the basket was turned over and the snake was gone. She found it under a wheelbarrow. I REALLY killed it that time. I took my cherrywood hiking stick and pulverized it's head. I showed it to two neighbors and we all agreed it was the biggest we have seen in years.
I'm not afraid of non-poisonous snakes either but they get my baby birds, so I relocate them.
Timmee is the hero here. He also kills black snakes.