Check what the Listing details say under Pet Deposit.
If there is no pet deposit, I would say, it may likely be a listing that will not take pets. This has to be confirmed with the listing agent, if you really think the property is a fit for you.
Assuming anything can be a big mistake.....providing people with accurate and reliable information is one of the basic services provided by real estate professionals. Always consult an agent on issues of this nature to be on the safe side.