The changes were brought about by selective breeding - choosing animals with desirable characters to breed from.

Choosing animals to be showcased for adoption is not easy.

In 1926, Tōshi chose animals as his primary subjects to distinguish himself from his father, who was a landscape printmaker.

"I chose animals that I found the most interesting," he said.

The idea has been taken up by other cities which have chosen animals for public art projects with painted fiberglass sculptures (see Similar projects).

Luckily they chose experimental animals which happened to include a species sensitive to one of the new agents under trial.

"It is particularly helpful to people in apartments, who sometimes choose animals that are too large or too active," said Miss Ragenovich.

In order to breed large mules, the original developers of the Poitou chose breeding animals with large features, such as ears, heads and leg joints.

Ruffner chose animals and an alien as her "alter images," she says, to suggest "how strange and foreign it feels not to be a biped."

"They choose animals that can survive the winter," she said.