66.NOT A TALE

According to a legend, X were formed during the Noah's Ark period. As per God's instructions Noah collects a pair of animals from each species. Likewise Noah had done so and had collected every species. But when the Ark was about be closed, two cats were late and hence during the closure of the Ark, had lost their Ys. Thus the new species of X was formed. X have been honored with a stamp from a nation with the below flag. Identify X.