[Theodore Roosevelt] was a naturalist on the broadest grounds, uniting much technical knowledge with knowledge of the daily lives and habits of all forms of wild life. He probably knew tenfold more natural history than all the presidents who had preceded him, and, I think one is safe in saying, more human history also.

Cheetah genes cooperate with cheetah genes but not with camel genes, and vice versa. This is not because cheetah genes, even in the most poetic sense, see any virtue in the preservation of the cheetah species. They are not working to save the cheetah from extinction like some molecular World Wildlife Fund.

Each time one of the medicine men dies, it's as if a library has burned down.
{Referring to potential knowledge from indiginous peoples of the medicinal value of tropical plants, speaking as director of the plant program of the World Wildlife Fund and having spent many months living with the Tirio tribe on the Suriname-Brazil border.]

Forests and trees make significant direct contributions to the nutrition of poor households ... [as] rural communities in Central Africa obtained a critical portion of protein and fat in their diets through hunting wildlife from in and around forests. The five to six million tonnes of bushmeat eaten yearly in the Congo Basin is roughly equal to the total amount of beef produced annually in Brazil – without the accompanying need to clear huge swathes of forest for cattle.

I believe sustainable use is the greatest propaganda in wildlife conservation at the moment.

I fully support the goal of species protection and conservation and believe that recovery and ultimately delisting of species should be the U.S. Fish and Wildlife Service’s top priority under ESA.

If in a given community unchecked popular rule means unlimited waste and destruction of the natural resources—soil, fertility, waterpower, forests, game, wild-life generally—which by right belong as much to subsequent generations as to the present generation, then it is sure proof that the present generation is not yet really fit for self-control, that it is not yet really fit to exercise the high and responsible privilege of a rule which shall be both by the people and for the people. The term “for the people” must always include the people unborn as well as the people now alive, or the democratic ideal is not realized.

My earliest impressions of wildlife and its pursuit retain a vivid sharpness of form, color, and atmosphere that half a century of professional wildlife experience has failed to obliterate or improve on.

One of the striking things about places heavily contaminated by radioactive nuclides is the richness of their wildlife. This is true of the land around Chernobyl, the bomb test sites of the Pacific, and areas near the United States’ Savannah River nuclear weapons plant of the Second World War. Wild plants and animals do not perceive radiation as dangerous, and any slight reduction it may cause in their lifespans is far less a hazard than is the presence of people and their pets.

Plans to protect air and water, wilderness and wildlife are in fact plans to protect man.

Scientists alone can establish the objectives of their research, but society, in extending support to science, must take account of its own needs. As a layman, I can suggest only with diffidence what some of the major tasks might be on your scientific agenda, but … First, I would suggest the question of the conservation and development of our natural resources. In a recent speech to the General Assembly of the United Nations, I proposed a world-wide program to protect land and water, forests and wildlife, to combat exhaustion and erosion, to stop the contamination of water and air by industrial as well as nuclear pollution, and to provide for the steady renewal and expansion of the natural bases of life.

The ocean is not just blank blue space but rather the habitat for amazing wildlife, and we have to take care how we use it. If we want to keep having the goods and services it provides, we have to treat it more carefully in terms of fishing and dumping.

There was wildlife, untouched, a jungle at the border of the sea, never seen by those who floated on the opaque roof.
Describing his early experience, in 1936, when a fellow naval officer, Philippe Tailliez, gave him goggles to see below the Mediterranean Sea surface.

Why then be concerned about the conservation of wildlife when for all practical purposes we would be much better off if humans and their domestic animals and pets were the only living creatures on the face of the earth? There is no obvious and demolishing answer to this rather doubtful logic although in practice the destruction of all wild animals would certainly bring devastating changes to our existence on this planet as we know it today… The trouble is that everything in nature is completely interdependent. Tinker with one part of it and the repercussions ripple out in all directions… Wildlife—and that includes everything from microbes to blue whales and from a fungus to a redwood tree—has been so much part of life on the earth that we are inclined to take its continued existence for granted… Yet the wildlife of the world is disappearing, not because of a malicious and deliberate policy of slaughter and extermination, but simply because of a general and widespread ignorance and neglect.

Wildlife management consists mainly of raising more animals for hunters to shoot.

Without knowing it, we utilize hundreds of products each day that owe their origin to wild animals and plants. Indeed our welfare is intimately tied up with the welfare of wildlife. Well may conservationists proclaim that by saving the lives of wild species, we may be saving our own.