Animal sounds in nature documentaries are often created using a technique known as "Foley". Foley artists are specialists who recreate everyday sounds using a variety of props, such as animal toys, household objects, and even their own bodies. They match these sounds to the actions and movements of the animals on screen. This technique allows filmmakers to add a realistic and immersive sound to the documentary footage.

There are a number of reasons why human-made animal sounds are used in nature documentaries:

- Accuracy: Foley artists can often recreate animal sounds more accurately and consistently than the original animal recordings, which can be influenced by factors such as distance, the environment, and the animal's behaviour.

- Control: Foley artists have more control over the sounds they create, allowing them to adjust and manipulate the sounds to fit the desired narrative and tone of the documentary.

- Cost-effectiveness: Using Foley artists can be a more cost-effective alternative to recording animal sounds in the wild, which can be time-consuming and resource-intensive.

- Versatility: Foley artists can create sounds for animals that are difficult or impossible to record in the wild, such as extinct species or animals that are located in remote or inaccessible locations.

Despite the use of Foley artists, many nature documentaries also incorporate authentic recordings of animal sounds, such as bird songs and mammal calls. These recordings are often mixed with the human-made sounds to create a more authentic and well-rounded soundscape.

The combination of Foley artistry and authentic recordings allows nature documentaries to bring viewers closer to the natural world, providing a more immersive and engaging experience for the audience.