What is the best prospect for an as yet undiscovered megafauna? And while I love me some Bigfoot, have a soft spot for a Skunk Ape, and want to ride an Ogopogo, I really am looking for a scientific answer, not articles from the Fortean Times.

From a strict zoological and statistical standpoint, if you are looking for a completely undiscovered megafauna (defined scientifically as an animal weighing over 100 pounds/45 kg), the short answer from the scientific community is: look to the deep ocean, specifically for cryptic marine mammals like beaked whales, or deep-sea sharks and cephalopods. Terrestrial megafauna like Bigfoot, the Skunk Ape, or a giant lake monster like Ogopogo are virtually impossible under modern ecological and observational models. However, science does project that large animals are still waiting to be formally described. Here is how modern biology ranks the best prospects for undiscovered megafauna.