When people seem to forget that only male Turkeys (or gobblers) will make the iconic gobble sound. Female turkeys make more of a clucking sound. Some folks seem to think that both male and female turkeys gobble. I have no idea where this misconception came from.
That the Pronghorn Antelope of western North America is an actual antelope. It isn't, it was just called an antelope because it fills a similar niche to the true antelopes of the Old World. It also isn't accurate to label it as a "Speed Goat" because it is not even a species of goat either, nor is it a type of deer or part of any other animal family. It is in its own family and genus and is actually more closely related to the Giraffe and Okapi than any true antelopes, goats, or deer. Yet I still often see it being confused with true antelopes of the Old World.
That there are only 3 species of bear in the world: The Grizzly Bear, Polar Bear, and Black Bear. This is so far from the case that it begs the question of whether the individual who believes this even knows what a bear is. According to World Atlas, there are eight currently existing species of bears in the world, including the Sun Bear, Sloth Bear, Asian Black Bear, American Black Bear, Spectacled Bear, Brown Bear, Polar Bear, and Giant Panda. Most people I've seen who believe this "3 Little Bears" myth are my fellow Americans, who, in the context of bear species living on the North American continent, are technically correct. However, this shows a clear lack of understanding of how widespread bears are and how many species there really are. Then there's the flip side of the coin where there are people who think that there's even more bear species like the Kermode Bear, Grizzly Bear, or Kodiak Bear, which are really just different subspecies of the American Black Bear and Brown Bear.
When visiting a local diner in my home state that my sister works at, the name of which is literally "The Bear" and whose symbol is a bear, with many bear-themed decorations, I saw this myth being spread in a way that really bothered me as a wildlife enthusiast and made me cringe. (And no, there was no actual bear meat being served at this diner, it's just a symbol of the diner and a marketing slogan). They had three main menus for "The three different types of bears" a breakfast menu titled "The Black Bear" a lunch/dinner menu titled "The Grizzly Bear" and a dessert menu called "The Polar Bear".
I mentioned it to my sister on the ride home that this was entirely untrue, and then I said "What about the Sloth Bear, Panda Bear, and Sun Bear?" and she was dumbfounded because she apparently didn't know that any of those existed (besides the Giant Panda, which she apparently thought was in the same family as the similarly named Red Panda, which is a whole other misconception entirely). This misconception may be completely unheard of to some, but you would be appalled by the number of misinformed people in the U.S. who actually seem to believe this.