Big Foot can be disproved with population biology. Based on the number of supposed sightings, there is not a large enough of a breeding population to keep the species alive and viable. No residual bone evidence found anywhere (surley some individuals must have died and left their bones lying about and humans have thouroughly combed the forests and mountains in the area they supposed occupy), modern or ancient.

Loch Ness has been solved. The Loch has a direct connection with the ocean at the north end of Scotland. A resesrch group a few years back traced the connection all the way to the ocean. They scoured the ocean between Scotland and Iceland and eventually found a species of fish that resembles the pictures, movements, and approximate dimensions consistent with the famous photo. Subsequently, the fish is capable of short term transition and can live in fresh water for a short while, then returns to the ocean.