What Grizzle bring with him in the classic The Swiss Family Robinson?

Grizzle brought home another one of his kind... an ass (donkey).

The horrible howlings seemed to approach nearer to us; at length, Fritz, who was leaning forward to listen as attentively as he could, threw down his gun, and bursting into a loud laugh, cried out, "It is our fugitive, the ass, come back to us, and singing his song of joy on his return!" We listened, and were sure he was right, and could not but feel a little vexation at being put into such a fright by a donkey. Soon after, we had the pleasure of seeing him appear among the trees; and, what was still better, he was accompanied by another animal of his own species, but infinitely more beautiful. I knew it at once to be the onagra, or wild ass, a most important capture, if we could make it; though all naturalists havedeclared it impossible to tame this elegant creature, yet I determined to make the attempt.