Our Ancient Survival Instinct, from Jeff Watson
It has been said by many biologists and vets that wild and domestic animals will appear to be healthy while they are really sick or terminally ill. It's a survival mechanism of the most basic order.
Reptiles often exhibit this type of behavior, within a 24 hour period going from relative calm to death spasms, then death. How many players in the markets put up fronts that all is well, while keeping their hand over a cut femoral artery because they are bleeding so badly.
Humans and animals use the same defense mechanism. Animals don't want to get eaten, and traders don't want the competition to know the weakness of their hands, so they act strong.