The animal care staff reported one frog with a swelling on the lower right mandible. No other animals in the colony were affected. On physical examination, the frog appeared alert and responsive.

It has a yellow orbital ring. The bill is curved with a black culmen extending over much of the upper mandible; the lower mandible is yellow with a black tip. Immature yellow-billed cuckoos look ...

The oldest insect fossil—a mandible (or jaw ... suggesting that insects were among the first animals to leave the oceans for land during the Devonian period some 400 million years ago.