Humans have studied tool usage among mammals for many years. A tool is any item found in nature that an animal uses for a specific purpose. This means that an animal is either using the tools for feeding, defending themselves, or for some other purpose. Charles Darwin noted how the primates he studied used tools to gather food and also for defense. Jane Goodall also famously studied primates and documented their usage of tools. Many animals use tools. Certain birds will create elaborate nests and stages to perform mating rituals. Octopus are known to create homes and gardens out of rocks and shells. Birds known as "fire hawks" will spread wildfire to scare up food. Although there is tool usage across many animal groups, we'll focus on a few examples from mammals.
Orangutans, for example, have long been known to use spear like tools to pry open fruit that has sharp barbs on it that otherwise makes it impossible to eat. Recently however, an Orangutan in Borneo was photographed using the spear to catch fish! Many species of coastal monkeys, like the crab-eating macaque, use rocks to smash the shells of crabs before eating them. Similarly, a sea otter uses stones to crack open hard shellfish like abalone. Tool usage is something that humans take for granted. Our ability to write on a computer or with a pen and paper, or build shelter, or hunt for food with weapons is so commonplace it's easy to forget how advanced of a skill it is. Studying the ability of animals to use tools, helps us understand how we evolved the way we did.