Bug,
Your landlord does not the the right to enter your apartment whenever she wants.
By law she must post an intent to enter at least 24 hours prior to her entering your home. The only time your landlord has the right to enter your apartment, with out posting an intent to enter notice, is if there is an emergency and the building is in immediate danger of damage ie., broken water pipe, flooding, an upstairs apartment or your apartment is leaking water, or a fire.
If there is nothing in your lease about reptiles legaly your landlord would have to put an addendum on your lease notifying you of the change to your lease and any addtional charges/deposits, otherwise it would hold up in court of law. She would then have to explain this to you and also have you sign it to prove that you were made aware of the new changes.
If you feel that you are being harassed, discriminated against, or treated unfairly there are organizations that protect the rights of renters. Look in the phone book under state, county or city agencies and you should find one.
Lee