This being a nature documentary, the importance of mating is heavily touched upon, and one scene shows a pair of Tyrannosaurus engaging in the act.

A sauropod steps on a giant frog, and we see it's remains.

There is a lot of cartoon/fantasy animal violence, almost all of which happens on-screen. Animals get bitten, hit, stabbed, mauled, even stepped on. Much of the violence is quite graphic.

Of particular note are:

One young dinosaur's jaw gets violently dislocated (though it recovers).

Another has its head bitten off (off-screen, but we see the corpse).

A pair of raptors bring down an adult Protoceratops.

One scene revolves around a dinosaur getting high on a strange mushroom. It starts hallucinating and gets dizzy. The sequence is accompanied with fittingly trippy visuals (as seen through the eyes of the dinosaur) and music.

Just about every scene.