Growling

Question
Following my other question, the rabbit has started to growl at anyone that goes near her, and she put her head down low with her ears back, does this mean there is omething wrong with her because up to now she has loved to be held and cuddled.
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The text above is a follow-up to ...

-----Question-----
I think my rabbits are about five months old,we were told they were both females.  But one as been mounting the other, but now the one that as been mounted as started to growl and bite the other, do you think we ended up with one of each and that one might be pregnant? should we separate them,or is there another reason the it is doing this.

-----Answer-----
Females will often mount each other to show dominance. However, it would be a good idea to make sure they are both females. If all they are doing is mounting (no biting, scratching, or fighting) it is okay, but if they are fighting they need to be seperated until both are spayed and healed. Two fighting rabbits (even two females) can hurt each other very badly.

Answer
That would be hormones acting up. She has reached sexual maturity (most rabbits reach it at 4 1/2 to 7 months, so she is right in that time frame). A hormonal female will often start acting aggressive. Getting a rabbit spayed will usually solve the problem.

However, before you do, make sure the other is also a female. A pregnant female can also suddenly switch personalities and become more aggressive (also due to hormones), so you want to make sure she is not pregnant before spaying so the growing babies do not die. If she is, wait until the babies are weaned away from the mom before spaying her.