Animals Are Awesome

Because birds have very high metabolic rates, they must eat a vast amount of food relative to their body weight. Yet because, usually, birds are flying animals, they must be light-weight. This means that their digestive systems must lightweight and efficient, and their musculature and skeletal structure is often as minimal as possible. Thus, birds have very few muscles in their heads compared to other animals. There are only a handful of tiny muscles responsible for opening and closing the jaw, limiting the strength of their bites.

To make up for this lack of bite strength, different birds have grown a range of adaptations. Sharp beaks, oral pouches to retain food, and oral papillae to grab onto food are common physical accoutrements.

Penguins have oral papillae (which are made of keratin) in order to grab onto and hold slippery fish in their mouths. Penguins do not fly, so they do not need to be light, but they still retain characteristics of their class, Aves.