The mouse in the last pic obviously got between 2 phases, but what killed the first one? Chewed through the insulation?
When I used to work on broadcast transmitters, mice were a constant source of problems. They often got across filter caps or rectifier stacks and were usually at least partially vaporized in the process. Talk about a wicked stench...
I found this on one of my Infrared inspections. The angle of the last picture makes it look like the mouse was between 2 phases. He was only attached to Phase "A". I believe the 2 mice were together and created a path between Phases "A" & "B". The second mouse was just hanging on the conductor. There was no damage to the insulation on any of the conductors in the transfer switch. After the mice were removed you could see where their fur was burnt onto the lugs of the switch. Should you call this a transfer switch or an electric mouse trap?