Dead bat on my balcony

Every morning one of the first things I do after waking up is to open the windows and the glass door to the balcony.  I don't leave them open through the night cause I'm afraid mosquitoes and cockroaches might invade.

Today when I opened the balcony's door, I found a bat laying on the floor.  It was laying face down, but grabbing with his feet the squiggy I use to clean the balcony.  I thought it was strange that a bat would be in that position, but soon I realized that it was dead!

I'm surprised to find this dead bat in my balcony.  I didn't even know that we have bats in this city!  I wasn't disgusted because it was a bat, I was disgusted to find a dead animal in my home.  I wonder what was the cause of death?  Can it eat cockroaches and mosquitoes?  I wish it were still around to catch those undesirables.