Boa struck at air???

[Eternalavenger]

so i came home from work tonight (around 2:30 am) and pulled the plug on my little guys (turned the lights off)...about an hour after...my male boa was in the water bowl and i came back in and flicked the light on...about 20 seconds later he just blatently struck into the air without warning and with no kind of provocation whatsoever. I have him and another (female) boa in a 40 gallon tank (deep) with several hides, a log, and 2 water bowl...the temp and humidity are a little irregular but would that cause him to become aggressive?

[gonesnakee]

Startled or scared & likely striking at shadows, Mark
P.S. snakes are best housed by themselves except for breeding purposes for a multitude of reasons