Bats and plumbing

[Yikes]

Yesterday I visited a relative's mountain cabin that has not been occupied for almost two years. Though the house exterior envelope is generally tight, I found a very small dead bat in the bathroom sink. The bathroom door and window were closed, and there's no bath exhaust fan.
I have a crazy theory that the water in the sink P-trap had evaporated, and the bat came down into the house via the plumbing vent at the roof, and worked its way through the drain into the bathroom.

Am I nuts, or does anyone know if bats have been able to enter homes via vent pipes?

 

[mtlogcabin]

Though the house exterior envelope is generally tight

Tight might not be good enough

https://www.batremovalpro.com/bat-resources/bats-in-toilets/

 

[my250r11]

Could be what happened. Have had scorpions come thru drains before.