23rd Oct: It's time for the second TV Tropes Halloween Avatar Contest, theme: cute monsters! Details and voting here.
General Taxonomy Mistakes Concerning MammalsOne of the most egregious examples is mistaking cetaceans (whales, dolphins, and porpoises) for fish. There's also those who insist that orcas, or killer whales, are just whales and not dolphins as well. Orcas are dolphins, which are toothed whales, so people are right about them being whales, but wrong about them not being dolphins. (Or those who insist that killer whales are not whales, but dolphins) Another example is the fact that many people mistake kinkajous for primates. Kinkajous are not primates, but a member of the raccoon family within the order Carnivora. There are also a lot of mammals are mistaken for rodents, including weasels (in Carnivora, closely related to seals and raccoons and more distantly to dogs), rabbits, hares, and pikas (order Lagomorpha, closely related to rodents but their own thing),note and shrews, moles, solenodons, hedgehogs, and moonrats (order Eulipotyphla, only very distantly related to rodents). We should note here that the weasels and Eulipotyphlans are more closely related to each other than the rodents, and the rodents are more closely related to humans than either of those.note And don't forget that humans are NOT descended from monkeys. We're descended from apes. And we still are apes. Great Apes, to be specific.note
General Mammal Anatomy MistakesPeople draw male kangaroos with pouches. The only extant (still existing) marsupial with both sexes having a pouch is the yapok, a semi-aquatic opossum native to South America. The Thylacine, or Tasmanian Tiger, exhibited this trait too, but it is now extinct. Rabbits are often drawn with paw pads, which they don't have in Real Life. Also, rodents and lagomorphs do not have canine teeth. Another example includes elephants drinking with their trunks instead of sucking up the liquid with their trunks and then squirting it into their mouths, like real elephants.
Other Mistakes Concerning MammalsAnother example is to refer to saber toothed cats, mammoths, and other Pleistocene megafauna as dinosaurs just because they are fierce and extinct and/or portraying them as being around during the Mesozoic era. Saber toothed cats are several groups of now-extinct, big-fanged cats that first appeared during the Eocene, going extinct during the Pleistocene. If something talks about canine social behavior and the writer isn't an ethologist, the information is at best hilariously out of date and at worst dangerously wrong.