Koalas and whales are both mammals. Therefore, they share characteristics common to all mammals, such as:
- Having fur, skin or hair
- Vertebrates (having a spinal column and internal skeleton)
- Nurture their young with mothers' milk
- Warm-blooded
- Three middle ear bones
- A single lower jaw bone
- Main systems of the body, e.g. digestive system, respiratory system, circulatory system, etc.
