The rain-filled potholes, set in naked rock are usually devoid of visible plant life but not of animal life. In addition to the inevitable microscopic creatures there may be certain amphibians like the spadefoot toad. This little animal lives through dry spells in a state of estivation under the dried-up sediment in the bottom of a hole. When the rain comes, if it comes, he emerges from the mud singing madly in his fashion, mates with the handiest female and fills the pool with a swarm of tadpoles, most of them doomed to a most ephemeral existence. But a few survive, mature, become real toads, and when the pool dries up they dig into the sediment as their parents did before, making burrows which they seal with mucus in order to preserve that moisture necessary to life. There they wait, day after day, week after week, in patient spadefoot torpor, perhaps listening - we can imagine - for the sounds of raindrops pattering at last on the earthen crust above their heads. If it comes in time the glorious cycle is repeated; if not, this particular colony of Bufonidae is reduced eventually to dust, a burden on the wind.
Rain and puddles bring out other amphibia, even in the desert. It's a strange, stirring, but not uncommon thing to come on a pool at night, after an evening of thunder and lightning and a bit of rainfall, and see the frogs clinging to the edge of their impermanent pond, bodies immersed in water but heads out, all croaking away in tricky counterpoint. They are windbags: with each croak the pouch under the frog's chin swells like a bubble, then collapses.
Why do they sing? What do they have to sing about? Somewhat apart from one another, separated by roughly equal distances, facing outward from the water, they clank and croak all through the night with tireless perseverance. To human ears their music has a bleak, dismal, tragic quality, dirgelike rather than jubilant. It may nevertheless be the case that these small beings are singing not only to claim their stake in the pond, not only to attract a mate, but also out of spontaneous love and joy, a contrapuntal choral celebration of the coolness and wetness after weeks of desert fire, for love of their own existence, however brief it may be, and for the joy in the common life.
Has joy any survival value in the operations of evolution? I suspect that it does; I suspect that the morose and fearful are doomed to quick extinction. Where there is no joy there can be no courage; and without courage all other virtues are useless. Therefore the frogs, the toads, keep on singing even though we know, if they don't that the sound of their uproar must surely be luring all the snakes and ringtail cats and kitfoxes and coyotes and great horned owls toward the scene of their happiness.
What then? A few of the little amphibians will continue their metamorphosis by way of the nerves and tissues of one of the higher animals, in which process the joy of one becomes the contentment of the second. Nothing is lost except an individual consciousness here and there, a trivial perhaps even illusory phenomenon. The rest survive, mate, multiply, burrow, estivate, dream, and rise again. The rains will come, the potholes shall be filled. Again. And again. And again.