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.

Two Million Years of Llamas

The camel family is one of the smaller mammal families in the present day, containing just seven species, four of which are domesticated. Thus, if you don't consider, say, dogs to be distinct from wolves at the species level, one could reasonably argue that there are only four. Although these are all considered to belong to the same subfamily (with all the other subfamilies being extinct), they still fall into two branches: the 'true' camels in the Old World, and their counterparts in the Americas.

It should come as no surprise that members of the family are noted for their ability to survive in arid environments with minimal water. They are, for example, more efficient at absorbing water from their stomach than ruminants such as cattle and deer, and genetically resistant to heat stress and ultraviolet radiation. Nonetheless, while the word "camel" doubtless conjures up an image of one or more of the three Old World species (that is, the dromedary and the wild and domesticated versions of the Bactrian camel), the family also includes those four American species.

The Genomics of Yellow Bats

In terms of species, bats are the second-largest order of mammals, after the rodents. New species are identified all the time, due in part to the relative difficulty of closely examining night-flying mammals, many of which sleep in hard-to-access caves. The current total stands at over a thousand, representing over 20% of all known mammal species. 

Within this huge group, there is, perhaps, rather more diversity than many people realise. While bats have probably not received the same level of attention as some other mammal groups, scientists have nonetheless long attempted to disentangle the relationships between all these subgroups. (Also, when I say they have received less attention, there's a mammal-centric bias here; it's probably still a lot better than, say lizards, let alone millipedes or the like). 

Euplerids: Falanoucs and Fanalokas

Fanaloka

The relationships of the native Madagascan carnivores were uncertain before the advent of genetic testing at the end of the 20th century. The majority were assumed to be mongooses, since that is very much what they looked like, but three species didn't quite fit the pattern. 

Two of these were, so far as anyone could tell from their physical appearance and habits, civets. They were often placed in their own subfamily, reflecting their distance from other civets, but nonetheless, they were thought to belong among the viverrids. Following genetic studies in 2003, however, it became clear that they belonged in the same group as (i.e. shared a unique common ancestor with) the Madagascan "mongooses". Since some of them clearly weren't mongooses, and since they had diverged from the real ones so long ago, the subfamily was split off and promoted to full family level, now including both the mongoose-like and civet-like species.

Eocene (Pt 4): Ancient Beasts of the European Archipelago

Propalaeotherium

The story of the evolution of the horse is one of the most commonly cited examples of evolutionary trends, often illustrated by a series of increasingly horse-like animals with an ever-reducing number of toes. The animal typically shown at the start of that series is, depending partly on the age of the picture, either Hyracotherium or Eohippus.

Hyracotherium was long regarded as the earliest known member of the horse family. In recent decades, it has become apparent that it wasn't really a horse, in the sense that modern horses don't descend from it or its relatives, and today we call the family it belonged to the palaeotheres. The North American Eohippus, on the other hand, despite long being thought to be identical to Hyracotherium, probably is a horse. The confusion between the two means that it's often difficult to tell which is being referred to in older sources. 

Looking for Leaves: the Travel Routines of a Koala

Animals inevitably have a preference for the particular habitat in which they live. Factors such as climate and the presence of suitable hiding and sleeping places are important, along with the presence of suitable food. While climate is less of a problem, food and shelter may be patchily distributed, with insufficient food in any one place to support the animal for long. The animal may also wish to avoid sheltering in any one place for too long, less predators find it easy to locate, and it also makes sense to travel between different patches of land if you want to find mates.

Thus, it can be important to know not merely which habitats a particular species of animal prefers, but how it moves about within that habitat to use to its best advantage. Does it tend to revisit particular patches of ground, and if so, how often? A herbivore, after all, wouldn't want to head back to a given place before whatever it had eaten there had had a chance to regrow.

Euplerids: The Not-Mongooses of Madagascar

Ring-tailed vontsira

There are around 35 currently recognised species of mongoose, spread between Asia and continental Africa. For the most part, they look fairly similar, with most being instantly identifiable as such. For most of the 20th century, however, they were also thought to live on Madagascar. In the last couple of decades, genetic studies have revealed that the Madgascan species, while related to the mongoose family proper, belong in a group of their own. That's partly because they diverged so far back in time, but also because that group includes some animals that manifestly aren't mongooses.

Today, in order to distinguish what we used to call "Madagascan mongooses" from the real sort, we tend to use the local Malagasy word and describe them as "vontsiras".