From Dragon to Cave Bear

In 1675, German physician Johann Paterson Hain published a detailed description of the bones of what he believed to have been a dragon. Such bones had been unearthed from German caves for centuries and identified as belonging to various mythical creatures, with unicorns perhaps the most popular - likely since one could sell supposed unicorn horns for their magical healing properties. Fortunately for us, his illustrations were highly accurate and we can identify them for what they really are.

Indeed, while naturalists continued describing such bones as belonging to fantastical animals into the 18th century, physician and rationalist Gregor Horst had beaten them to the punch, pointing out as early as 1656 that bones recovered from Unicorn Cave (yes, that is its actual name) looked remarkably like those of "bears, lions, and humans". Today, we can look at Paterson Hain's original illustrations and confirm that he had produced the first known published drawings of the bones of a cave bear.

Moulting Marmots

Moulting is a feature of mammalian physiology that will be familiar to pet owners worldwide. While it's not present in all mammals, it is very widespread despite the fact that, when you think about it, it's obviously costly to the animal in question. Why shed and replace a large amount of hair in a short time when you could replace it bit by bit as humans do?

The fact that so many mammals, of widely different kinds, moult to at least some extent shows that it must be an evolutionary ancient phenomenon. In fact, it turns out that animals have probably been moulting since before they even had hair. We can tell this because it's not unique to mammals. For instance, birds moult their feathers, and the process is similar to hair moulting in mammals. More significantly, perhaps, moulting has the same underlying mechanisms as reptiles periodically shedding their skin and can be tied back to sloughing in fish and amphibians as well. 

You Scratch My Back...

One of the most widespread behaviour patterns among non-human primates is their habit of grooming one another. Technically referred to as "social grooming" or "allogrooming", this refers to cleaning the fur of other animals, removing ticks and other parasites. In addition to the obvious health benefits, this also helps maintain cohesion among social groups that can be structurally complex. Indeed, it's generally thought to be one of the main reasons primate societies are so sophisticated in the first place.

Many mammal species live solitary lives, at least outside of the mating season. For those, there would be little opportunity for social grooming and no wider benefit to be gained from it if there was. Self-grooming or "autogrooming" - such as licking one's own fur - may well be sufficient for them. But, of course, primates are not the only social mammals, and many of those other animals have fur in which parasites could hide, so it's reasonable to ask if allogrooming really is unique to primates.

Antilopine Antelopes: Dwarf Antelopes of Eastern and Central Africa

Oribi

The term "dwarf antelope" can reasonably be applied to many different kinds of antelope that are smaller than, say a typical goat. In this common sense, it's not a precise term, and could refer to species that belong to quite different branches of the antelope family tree. When mammalian zoologists used the term in the 20th century, however, it was often more precise, referring to those thought to be most closely related to the gazelles as a branch within the "antilopine" subfamily of "typical" antelopes.

Technically, these dwarf antelopes were collectively referred to as "neotragines" and assumed to be a natural grouping within the antelopes more widely. Genetic analysis over the last couple of decades has muddied these waters considerably, not least because the genus for which the branch was named, Neotragus, turns out not to be closely related to the gazelles, and is something else entirely. Even if we look solely at those dwarf antelopes that we can still say belong to the antilopine subfamily, it turns out that they don't have a single common ancestor. Specifically, one of them is more closely related to gazelles than it is to any of the other members of its purported evolutionary branch.