Final answer:
The aardvark, a nocturnal African mammal, is known for digging extensive burrows up to 43 feet long. Llamas are native to South America, not the Old World. The chimpanzee has a larger brain-to-body ratio, indicating higher complexity in behavior.
Step-by-step explanation:
The African mammal known for digging burrows up to 43 feet long is the aardvark. The aardvark is a nocturnal mammal native to Africa and is also known as the 'earth pig.' It uses its strong claws to dig burrows for resting and to search for its primary food source, ants and termites. This ability to create extensive burrows distinguishes the aardvark from other African mammals such as the African Elephant, Chimpanzee, and Cheetah.
Regarding the origins of various animals, the llamas did not originate in the Old World of Europe, Africa, or Asia. Instead, llamas are native to South America. In contrast, cattle, sheep, and pigs have their origins in the Old World.
In terms of relative brain size, the chimpanzee is noted for having a larger brain-to-body ratio compared to other mammals, which is associated with their complex behaviors.