Deduction

A woman walked into the kitchen to find her husband stalking around with a fly swatter

'What are you doing?' She asked.

'Hunting Flies' He responded.

'Oh.! Killed any?' She asked.

'Yep, 3 males, 2 Females,' he replied.

"Wow, how could you tell?," she asked.

"3 were on a beer can, 2 were on the phone"