Two-legged

Plato having defined man to be a two-legged animal without feathers, Diogenes plucked a cock and brought it into the Academy, and said, "This is Plato’s man." On which account this addition was made to the definition,—"With broad flat nails."

A two-legged donkey can become general and remain a donkey.

To the best of my knowledge, humans are the only two-legged mammals in existence.

What is it that having one voice becomes four-legged and two-legged and three-legged?

two-legged animals    two-legged shears

And that thing made of ſound and ſhovv / VVhich mortals have miſnamed A Beau, / (But in the language of the ſky / Is call'd a tvvolegg'd butterfly) / VVill make your very heartſtrings ake / VVith loud and everlaſting clack, […]

The four-leggeds blamed the cleansing on the humans, and decided to destroy all two-leggeds.

Because most of the animals had learned to distrust the two-leggeds, they shrank back into the forest.

It was a serious race, for the two-leggeds —human beings and birds— were racing the four-leggeds to determine which should feed the others.