Poison ivy isn't an ivy, and poison Oak isn't an oak. They are both anacardiaceous shrubs, members of the cashew family.

Goldilocks was originally named Silver Hair.
The gray whale is actually black
The electric eels are not eels. They are a fresh water fish native to South America and related to the carp.
Myth: IOU stands for "I owe You." Truth: IOU from a borrower originally meant "I Owe Unto" followed by the name of the person who loaned the money.
Horned toads are not toads - they are lizards.
The Dead Sea is not a sea, it's actually a lake.

Myth: The Chameleon changes color to match its background. Truth: Chameleons do have the ability to change color instantly, but not to match the color of their surroundings. The color shift is a reaction to fear or extreme changes in temperature or light.
Philadelphia Brand cream cheese was not originally manufactured in the City of Brotherly Love, but rather in the Big Apple, New York. The cream cheese was branded Philadelphia to take advantage of the reputation for fine food the city had a that time.
Myth: Centipedes have a 100 legs. Truth: Centipedes number of appendages range from 28 to 354, depending on the species. And millipedes don't have a thousand legs, either.
Horseshoe crabs are not crabs. They are survivors of a species that became extinct 175 million years ago. Their closest modern relatives are scorpions and spiders.
Buttermilk does not contain butter. It is a by-product of the butter-making process and contains less fat than whole milk.