Squirrels act as inductors in DC circuits. Only once though. There's a high current surge that drops to zero as they turn rapidly into a carbon resistor!
Note to self: Don't design any circuits that incorporate these animals. Squirrels make terrible fuses.
We had a different problem. They chewed through the fibre cables between our offices to get the fiberglass sheath for their nests. Eventually they ran Ethernet underground because they'd have broken it again in a couple of weeks.