Ancient Ghosts

The other day as I was musing over my paranormal experiences, a friend asked "Why are there only reports of ghosts within the past 200 years?"

It is a good question. Why do most ghosts seem to be from the past 200 years.

On a global scale there are ghosts and hauntings that do date back some 2,000 years plus.
Most of these places are ancient battlefields, tombs, and monuments to past civilizations.
Europe, China, Japan, and the Middle East have tales of spirits and hauntings that date back many centuries past. Yet we also need to remember, that most ancient places may have been spiritually cleansed by the cultures that dwelt around an active hotspot. Some places are ritually sanctified as well, and may hold the spirits of the ancient dead in suspension until such a time that area is defiled by human hands or by nature.

The other factor I would say is Pathos-"the quality or power in an actual life experience or in literature, music, speech, or other forms of expression, of evoking a feeling of pity or compassion". A spirits haunting can last for only so long, over the course of years spirits can just fade away if no one remembers them. The turn of centuries can send a haunting into the arms of oblivion if no one remembers. Also sometimes spirits finally let go and just dissipate or move on.
Lastly some may enter a hibernative state in which they suspend activity until a certain event
takes place or awakened.

This may also explain why ghosts of animal are not as present. Hardly anyone remembers the passing of an animal, but that is not to say that they are not there. According to a Hunter's methodology, animal can detect the presence of a spirit or entity. So there are animal spirits, but they probably move on rather quickly, however domestic animals may run by our rules too.