The instinctive need to be the member of a closely knit group fighting for common ideals may grow so strong that it becomes inessential what these ideals are.

Natural selection does not give any preference at all to anything that, in the long run, could be advantageous for the species but blindly rewards everything that, momentarily, affords greater procreative success.

The appeal of the cat lies in the very fact that she has formed no close bond with [man], that she has the uncompromising independence of a tiger or a leopard while she is hunting in his stables and barns: that she still remains mysterious and remote when she is rubbing herself gently against the legs of her mistress or purring contentedly in front of the fire.

In nature we find not only that which is expedient, but also everything which is not so inexpedient as to endanger the existence of the species.

The human mind, in taking us down the path of technocracy, has become the adversary of life itself and collaterally the adversary of the human soul.

It ought to be realized by all dog owners that obesity shortens a dog's life quite considerably, a life which is much too short anyhow.

We do not take humor seriously enough.