The following are my favorite prehistoric animals: saber-toothed tigers, dire wolves, and megalodons.
The prehistoric cousins of the modern elephant are the woolly mammoth, the mastodon, and the Columbian mammoth.
Are is a linking verb, so you don’t need a colon to introduce this list.
Steve looked at the mammoth display with Ruhi, Juan, and Andrea.
With is a preposition, so there’s no need for a colon here.
Saber-toothed tigers are famous for one thing: their enormous fangs.
In this example, their enormous fangs illustrates the one thing for which saber-toothed tigers are famous.
I can’t decide which is more impressive: the tusks of the woolly mammoth or the fangs of the saber-toothed tiger.
Here the information following the colon explains the items (the tusks of the woolly mammoth or the fangs of the saber-toothed tiger) the speaker is deciding between.
If there was one thing Henry knew about the Pleistocene Epoch, it was this: It was very cold.
In this example, the information following the colon is a complete sentence, so it is capitalized. It was very cold explains the one thing Henry knew about the Pleistocene Epoch (the last ice age!).
- Use a colon to introduce a quotation