Colonies of breeding king penguins resemble the movements of molecules in a 2D liquid, as they attract and repel one another in a constrained planar space. This "liquid" organization and structure enables breeding colonies to protect themselves against predators while also keeping members together.

See the source article by following the link below:
Colonies of breeding king penguins resemble the movements of molecules in a 2D liquid, as they attract and repel one another in a constrained planar space. This "liquid" organization and structure enables breeding colonies to protect themselves against predators while also keeping members together.