Wolves, Foxes, and Food

Large scary predators are, by their nature, rare. There simply can't be too many of them, or they would run out of food to eat, something typified by the trophic pyramid often seen in biology textbooks: plants are eaten by herbivores are eaten by carnivores are eaten by bigger carnivores, with each step necessarily having a smaller total mass. The reality is, of course, somewhat more complex than this simple chain would suggest, most obviously because it ignores omnivores and decomposition.

But the basic idea holds, and apex predators - those that are large enough that nothing else normally eats them - exist in much smaller numbers than herbivores or smaller carnivores. This means that, relative to their numbers, they have a disproportionate effect on the ecosystem within which they live. Take away the apex predators and, even though there weren't very many of them to begin with, you will radically change the local ecology.

And, because they are relatively few in number, apex predators tend to be especially vulnerable to being wiped out. That's even assuming that humans don't focus on them deliberately out of fear, whether for their own lives or for the good of their livestock. Globally, apex predators are declining. (On this blog, we're mostly interested in mammals, but consider, for example, that at least eight of the 23 species of crocodile/alligator are currently thought to be endangered).

Wild Mammals of London

Arguably the single biggest threat to the continued survival of animal and plant species is loss of habitat. Even if an animal isn't actively hunted, the ever-growing human population means that there are simply fewer suitable places for them to live. Logging and the expansion of agriculture are probably the biggest factors here, at least in terms of the area affected, but it's hard to argue that the recent growth of urban sprawl isn't another.

The urban environment is obviously a difficult or impossible one for most wild mammals to exploit. House mice and rats are an obvious exception, and there are also domesticated pets, but for truly wild creatures it's a different matter. While it may no longer have (say) bison or wolves, upstate New York is still home to seven species of shrew, three moles, four hares or rabbits, 22 different kinds of rodent, ten bats, nine mustelids, two foxes, and three deer, plus coyotes, bobcats, raccoons, striped skunks, and black bears. Manhattan... not so much.

The Dog Family: Red and Corsac Foxes

Red fox

Most members of the dog family can be described, broadly speaking, as "foxes". The term "fox" no longer has a strict scientific meaning, since it encompasses two separate lines of evolution that aren't directly related to one another. Furthermore, as we'll see in a few month's time, there are some animals within those lineages that really aren't foxes at all, as we'd normally think of the word.

Nonetheless, it's a term that's widely used, and is taken to refer to small to medium-sized canids that have have bushy tails, prominent ears, pointed snouts, moderately long legs, and so on. The archetypal such animal, and the one that most people in the Northern Hemisphere likely think of first when the term "fox" is used without any further qualification, is the red fox (Vulpes vulpes).

The red fox is, in fact, the largest of the "true" foxes (as opposed to those of the second, younger, evolutionary line, which are actually more related to wolves). It is also perhaps the most brightly coloured of all foxes, although there is some variation in the coat colour, with brown, yellowish, and even silvery-grey individuals. None of these match directly to any of the more than forty subspecies that have been identified over the years, although it's likely that many of those represent rather finer hair-splitting than is actually required.

Predator v Predator

Herbivores eat plants, carnivores eat herbivores. That, at it's simplest, is how food chains work. But, of course, food chains are almost never that simple in reality. For a start, it's surely obvious that, given the chance, big carnivores eat small carnivores. They generally aren't a high proportion of their diet, not least because the sort of parasites you might find inside a small carnivore may not be very healthy for the big ones, either (mammalian carnivores being fairly closely related, in evolutionary terms). But they'll certainly do it.

Carnivores eating other carnivores is called intraguild predation, which sounds like it ought to have something to do with World of Warcraft, but doesn't. (Unless your characters eat one another, which I'm fairly sure the game doesn't allow). Inevitably, such predation means that the lifestyle of a small carnivore is somewhat different from that large one. It's not just being eaten themselves that they have to worry about, either. There's also the risk of something larger coming along and pinching the dinner that you just spent so much time catching. Which, while we're on the technical terms, is called kleptoparasitism.

Should I Stay or Should I Go?

Although they are hardly alone in this, mammals are noted for their care of their offspring. Yet many of them are solitary animals, and the young leave home as soon as they are able to survive on their own, so that the only groups seen are when a mother is caring for her children. But, of course, many mammals live in herds, packs, or other groups, with at least some individuals staying with their parents once they grow up.

But, even in herds, some animals do leave home, to establish or join new groups elsewhere. How do they make this decision as to whether to leave or stay? For many, its a fairly simple rule: the males leave, and the females don't. That means that a herd or other group is dominated by a core of females descended from a single matriarch, while the males have generally come in from outside. Initially, in most cases, the males wander about looking for a new group, perhaps together with one or two other young males in a similar situation, until they eventually find someone that will take them in. This ensures that they don't end up mating with their own female relatives, and keeps the gene pool as wide as possible.