Big Question: What is the biggest animal on Earth?
What is the biggest animal species on Earth?
According to BBC Earth, an adult of this animal can weigh as much as 40 elephants or 30 Tyrannosaurus rex.
So what is it?
We asked Aaron from CBBC's One, Zoo, Three to help us answer this excellent question from Xaynab, age 10 from Amersham in England.