In the book of Job chapter 40: 15- 24...we see The Creator demonstrating his greatness by using a creature Job was obviously aware of as an example. The beast behemoth was mentioned and described. It was said to:
1. Eat grass like the ox.
2. It's bones were like bars ọf bronze (in other words really big and strong)
3. It could wade into the river Jordan and feel relaxed upon a rushing tide.
4. It's tails was swung like a cedar tree.
5. It had enormous strength in it's limbs and belly.
6. It was called the "first amongst the works of God" meaning it precededed man.
Some have said this behemoth was maybe a hippopotamus BUT the tail of a hippopotamus is comparatively small to its size when compared to other animals. The tail of a behemoth was said to be as large as a cedar tree.

Another group of critic say it might have been an elephant but again elephants have relatively small tails.

I believe an animal large enough to bask in the Jordan river, eats grass and has a tail as large as a small tree fits the description of what we call dinosaurs today...

A sauropod

A cedar tree

A hippopotamus