• Nest-building in fish: Shell-dwelling cichlids build nests from empty snail shells, using them for shelter and to raise their young.
• Stereotypical behavioral sequence: The fish follow a set sequence of actions to bury the shell in the sand. However, they can respond flexibly to variables, such as the shape of a snail shell.
• Innate behavior: Even fish with no prior exposure to snail shells know how to transform one into a nest. However, it takes them longer the first time and they become more skilled with practice.
• Cognitive components: Alongside instinctive behaviors, the ability to adapt and learn also plays a role in nest-building.