In the forest martens and sables are much less difficult to approach than many other wild animals; but they nevertheless display a keen aversion to the neighbourhood of human dwellings, which they never voluntarily approach. Martens and sables, unlike their smaller relative the stoat or ermine, do not turn white in winter; for the very sufficient reason that, on account of being arboreal animals, they would be extremely conspicuous in such a livery. They are so relentlessly hunted for the sake of their valuable fur, that it is a marvel they have not long since been exterminated from many portions of their habitat. The value of the skins of the ordinary European marten varies from eight to twelve shillings, but Russian and Siberian sable commands a much higher price in the market. THE LEOPARD (_Felis pardus_) It is not a little remarkable that three such closely related animals as the lion, the tiger, and the leopard or panther (for these two names really indicate the same species) should exhibit such striking dissimilarity in their type of colouring. The explanation of the difference in this respect is, however, probably to be found in the diversity of habit. Neither the lion nor the tiger can climb; and as the former is mainly an inhabitant of open and more or less desert country, it has assumed a uniformly sandy coat to accord with the tawny hue of its surroundings. The tiger, on the other hand, resorts more to covert, and has therefore adopted a livery suitable to such situations, or, at all events, one which tends to break up the general outline of the body. From both its larger cousins the leopard differs by its arboreal habits, and this may to a great extent account for its spotted type of colouring, which harmonises well with the chequered shade thrown by the foliage on the horizontal and gnarled branches of forest-trees. It is, however, important to notice that the dark markings on the fur of an ordinary leopard are not solid black circular spots, but take the form of rosettes of irregular black patches enclosing a centre of darker tint than the general ground-colour of the fur. Such a type of colouring seems to be one specially adapted to a partially arboreal life, for in the purely terrestrial hunting-leopard (_Cynælurus jubatus_), as well as in the smaller African cat known as the serval (_Felis serval_), the markings all take the form of solid circular black spots. It is further noteworthy that the Amurland race of the leopard (_F. pardus villosa_), which inhabits a country where the forests are coniferous and therefore ill-adapted for climbing by a large animal, the spots are in the main solid and more or less nearly circular.