“Our planet, the Earth, is, as far as we know, unique in the universe. It contains life. Even in its most barren stretches, there are animals. Around the equator, where those two essentials for life, sunshine and moisture, are most abundant, great forests grow. And here plants and animals proliferate in such numbers that we still have not even named all the different species. Here, animals and plants, insects and birds, mammals and man live together in intimate and complex communities, each dependent on one another. Two thirds of the surface of this unique planet are covered by water, and it was here indeed that life began. From the oceans, it has spread even to the summits of the highest mountains as animals and plants have responded to the changing face of the Earth.”

“Better to be an animal than a man, an insect than an animal, a plant than an insect, and so on. Salvation? Whatever diminishes the kingdom of consciousness and compromises its supremacy.”

“It is humankind's duty to respect all life, not only animals have feelings but even also trees and plants.”

“What, then, is the animal? First of all, a system of plant-souls. The unity of those plant-souls, which unity nature itself produces, is the soul of the animal. Its world is therefore partly that of the plants — its nourishment, for instance, it receives partly through synthesis from vegetable, and through analysis from animal nature — and partly that of the animals, whereof we shall speak directly. Each product of nature is an organically in-itself completed totality in space, like the plant. Hence, the unknown x which we are looking for must also be such a whole or totality, and in so far it must also have a principle of organization, a sphere and central point of this organization; in short, the same which we have called the soul of the plant, which thus remains common to both. … The animal is a system of plant-souls, and the plant is a separated, isolated part of an animal. Both reciprocally affect each other.”

“By far the most dangerous animal on the planet was an invasive species of ape.”

“All the living hold together, and all yield to the same tremendous push. The animal takes its stand on the plant, man bestrides animality, and the whole of humanity, in space and in time, is one immense army galloping beside and before and behind each of us in an overwhelming charge able to beat down every resistance and clear the most formidable obstacles, perhaps even death.”

“Man is a rational animal, and if human affairs are hard to regulate, his twofold nature is usually the cause. Reason is something ultimate; it would be the same in another planet, or in another universe, as it is here. Animal nature is something contingent; it might have been different. Our life is a compromise, a blend between the animal and the rational.”

“We're animals. We're born like every other mammal and we live our whole lives around disguised animal thoughts.”

“Warm-bloodedness is one of the key factors that have enabled mammals to conquer the Earth, and to develop the most complex bodies in the animal kingdom. In this series, we will travel the world to discover just how varied and how astonishing mammals are.”

“But it is we that choose to divide animals up into discontinuous species. On the evolutionary view of life there must have been intermediates, even though, conveniently for our naming rituals, they are usually extinct.”