Penguins are flightless birds, or avifauna. They used to fly in the past, but it is thought that they evolved and stopped flying. Instead, they became good at swimming & diving.

When viewed from underwater, their white bellies allow them to blend in with the sunlight, making them harder to spot by other creatures.

The maximum is about 7 to 8 years. However, very few sardines live this long in the harsh natural world. Most are eaten by other creatures.

It is said that it is the closest to spiders in terms of classification.

Rays have gill slits on the ventral side of their bodies, while sharks have gill slits on the side of their bodies.