Heat cycle cause aggression?

My female has just ended her heat cycle (well the actual bleeding part) about a week ago. Now we've noticed her aggression to the other one (5 month old male) has been almost over the top lately. Before her cycle, she was happy go lucky with him, never growled at him when playing... Now she is a little turd! She growls at him any time he gets close to what she's chewing on (which before she'd just let him take it away). She's nipped at him and made him yelp numerous times, and she's made him bleed a few times also. Of course he loves every minute of it and just goes back for more, which in turn causes more ruckus!

Do you feel that her hormones have changed and caused this new behavior, or maybe her lightbulb is just turning on coincidedly to her cycle?

I know this is pretty normal, and especially when toys come into the picture - but the behavior just started and it's a complete 180 from before.

 

its lot to do more with his age than anything"she is just setting him straight"..unless hes trying to breed with her..after there heat there real sensitive.lets just say she doesn't look at him as a pup anymore.

 

They are maturing. It's very plain & simple. Just be ready to crate & rotate as their time of togetherness may be coming to an end.

 

I'm also researching how to set up a good chain setup. I know that once it happens, someone will need to be on it. Plus I'm still debating on doing that with the male anyways - he's an outdoors dog.