You can’t usually smell your own house (or perfume) because of a survival instinct called ‘olfactory adaptation.’ The brain is always looking for new, unusual, or changing smells as a sign of possible danger, so it ignores smells that have become familiar.  (, )

The scientists who first discovered the platypus thought it was fake. Although indigenous Aboriginal people already knew of the creature, European scientists assumed an egg-laying, duck-billed, beaver-tailed, otter-footed, venomous mammal had to be an elaborate hoax.  (, )