Human: What are the most important differences between the hippopotamus and the elephant? Assistant: 
The main difference between the hippopotamus and the elephant is their size. The hippopotamus is much smaller than the elephant, with an average weight of around 1,500 kilograms (3,300 pounds). The hippopotamus also has a longer snout than the elephant, which helps it to root for food in muddy waters. The hippopotamus also has a shorter lifespan than the elephant, with an average life span of about 40 years compared to 80 years or more for the elephant.