What is the weight and length of the Loch Ness Monster?

That will not be known until one can be captured or photographed with some reference scale. It is estimated to be the size of a dinosaur. == It's estimated length is 15 to 20 feet, and it's weight maybe about 2, 500 pounds. Most size estimates of Nessie are twenty to fifty feet long. But a population of creatures would have to have individuals in various stages of growth. It stands to reason that one creature could not survive for centuries, so if there is anything in there, it would have to have a population capable of sustaining itself for years.