A ferret, dog, or cat which is four (4) months of age or older shall be licensed by the owner as herein provided. The licensing requirement of this Subdivision shall not apply to any animal belonging to a nonresident of the County and kept within the boundaries of the County for not longer than thirty (30) days. All such animals shall, at the time of entry into the County, be properly vaccinated against rabies and, while kept within the County, shall meet all other requirements of this Subtitle.