Goo Goo G'joob

"Pinnipeds" is the technical term for flipper-footed aquatic mammals that are able (although often with difficulty) to move about on land. Although there had previously been some speculation on the point, we now know that they are a natural group of animals, all descending from a single distant ancestor. They are carnivorans, more closely related to dogs than to cats and probably represent the third major branching within the living dog-like carnivores, after the dogs and bears, but before (for example) the raccoons, skunks, and weasels.

The living species of pinniped are placed within three families, although one or two extinct ones are also recognised. Most pinnipeds belong to the Phocidae, or "seal family". While the term "seal" is often used in modern English to refer to pinnipeds in general, the seal family proper consists of animals especially well-adapted to living in the water. They lack visible ears, and their hind limbs are arranged so to be efficient for propulsion underwater, but almost useless on land, forcing them to haul themselves about using their front flippers only.

Euplerids: Madagascar's Top Mammalian Carnivore

The native mammalian carnivores of Madagascar are mostly obscure to those of us in the West. The one possible exception, thanks to the Madagascar animated film franchise, is the fossa (Cryptoprocta ferox). Often spelt with a single 's', especially in more modern sources, and typically pronounced "foosa", this is the largest and most potentially dangerous of all the island's native mammalian predators.

Having said which, it's not especially big compared with predators elsewhere. There is little need to be a large carnivore when the island does not have, for example, any native antelopes. On average, they are about 75 cm (30 inches) in body length, not counting a cat-like tail that adds about the same length again. Adult females weigh around 6 kg (13 lbs), while the largest males can reach 8.5 kg (19 lbs), about the same as a West Highland terrier. 

Exactly where they fit within the mammalian family tree was long a source of confusion, given a mix of features resembling a range of other animals. When English zoologist Edward Turner Bennett first described the animal in 1833, he considered it to be a type of unusually large civet. So it remained for a hundred until it was moved to the cats in the 1930s, back to the civets in the 1940s, and then to the mongooses in the 1990s. Over the next ten years or so, arguments continued back and forth between all three of these options until genetic studies finally settled the matter in 2003. 

The First Cows In Europe?

When we look at scientific lists of animals, we usually see them placed into neat groups based on their relationships: families, subfamilies, and so on. These are, however, entirely human constructions, and nature is rarely so tidy in reality. Even for mammals, which have been more thoroughly studied than, say, fish or invertebrates, disagreements can arise, and details can change.

At least in the case of mammal groups above the species level, the relationships are faily well understood by this point, thanks to the advance in molecular and genetic studies over the last couple of decades. Disputes are more likely to arise when we question how broadly we should define a particular group, and what taxonomic level it might have. (The latter, of course, are entirely artificial; the cat family is provably a 'real' thing, but the fact that we call it a 'family' rather than giving it some other rank is essentially arbitrary).

This becomes a much bigger issue when we look at animals we know only from fossils. For one thing, we will have fewer, and generally less complete, specimens to examine. Furthermore, unless they are really recent, genetic analysis is out of the question. But, on top of all of that, when we travel back in time, lines become inherently blurred. There's always going to be the question of where exactly the 'not yet X' becomes 'X', even if we had perfect information about them. Which we don't.