20th Century Fox

26 May

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From the Free Online Encyclopedia Wikipedia

In many cultures, the fox appears in folklore as a symbol of cunning and trickery, or as a familiar animal possessed of magic powers.

By far the most common and widespread species of fox is the red fox (Vulpes vulpes), although various species are found on almost every continent.

Red Fox

The word fox was inherited from Old English, itself from Proto-Germanic *fuhsaz; compare West Frisian foks, Dutch vos, and German Fuchs. This in turn derives from Proto-Indo-European *puḱ- ‘thick-haired; tail

Male foxes are known as dogs, tods or reynards, females as vixens, and young as cubs pups or kits. A group of foxes is referred to as a skulk, leash, troop, or earth.

Fox hunting is an activity that originated in the United Kingdom in the 16th century. Hunting with dogs is now banned in the United Kingdom,though hunting without dogs is still permitted. It is practiced as recreation in several other countries including Australia, Canada, France, Ireland, Italy, Russia and the United States.

In some countries, foxes are major predators of rabbits and hens. Population oscillations of these two species were the first nonlinear oscillation studied, and led to the now-famous Lotka-Volterra equation.

The Lotka–Volterra equations, also known as the predator–prey equations, are a pair of first-order, non-linear, differential equations frequently used to describe the dynamics of biological systems in which two species interact, one a predator and one its prey. They evolve in time according to the pair of equations:

dx}/{dt} = x(α – βy)

{dy}/{dt} = – y(γ – δx)

where,

x is the number of prey (for example, rabbits);
y is the number of some predator (for example, foxes);
{dy}/{dt} and {dx}/{dt} represent the growth rates of the two populations over time;
t represents time; and
α, β, γ and δ are parameters describing the interaction of the two species.

The Lotka–Volterra system of equations is an example of a Kolmogorov model,which is a more general framework that can model the dynamics of ecological systems with predator-prey interactions, competition, disease, and mutualism.

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