‘A dog is for life — not just for Christmas!’ This slogan is intended to warn potential purchasers of the long-term consequences of pet ownership: not merely dogs, and not merely at Christmas. Yet thousands of households buy pets to amuse the children, and are stuck with them when the children are no longer amused. Now Daedalus has the answer. He is inventing the short-life pet.

In principle, no mammal can live for ever. At every cell division, one unit is lost from the telomere sequence on each of its chromosomes. When the entire telomere sequence has gone, the cell can no longer divide. Its vital reserve is exhausted. So Daedalus plans to shorten the telomere sequence in pet animals. His biologists are taking fertilized dog, cat and hamster ova, and cultivating them in vitro by standard methods.

Every animal, of course, arises from a single fertilized ovum. It divides into two cells, then into four, and ultimately into a complete fetus. If at the two-cell stage the cells are separated, they go on to develop into identical twins. The DREADCO team members are encouraging this process. Each time an ovum divides into two, they separate the two cells. When these reach the two-cell stage, these are separated again, and so on. At each cell-division, one telomere unit is lost from the cells' chromosome termination. After many such divisions, Daedalus will have millions of identical telomere-depleted ova of the chosen pet species. They will be implanted into surrogate mothers of the same species, and brought to term.

The resulting identical youngsters will command vast prices in the pet market. Children will adore their fluffy appeal. Canny parents will appreciate their brevity. Almost as soon as their appeal has waned, their telomere sequences will be exhausted, and they will drop dead.

Daedalus is not sure what they will die of. It won't be senility; brain cells hardly divide at all. Gut cells divide very fast, so it may be indigestion. But one standard feature of old age, in Man as in animals, is the increasing embrittlement and fragility of connective tissue. So their fibroblast telomeres may give out first. Like other toys, Daedalus's short-life pets may just fall to pieces.

The Further Inventions of Daedalus (Oxford University Press), 148 past Daedalus columns expanded and illustrated, is now on sale. Special Nature offer: m.curtis@nature.com