You can do exactly the same things with an academic essay introduction. For example:
Naked mole rats, or Heterocephalus glaber, possess a highly unusual set of traits.
Oh, really? Please tell me more. The readers’ curiosity is up, and you haven’t done anything fancy or complex, just as in example two.
Once you’ve grabbed your reader, you have to make them relax and engage. In the funnel introduction, you do this with your second, smaller, sentence, which acts as a bridge between the opener and the thesis. You can, though, use more than one sentence to do this:
Naked mole rats, or Heterocephalus glaber, possess a highly unusual set of traits. First, as the name implies, they are hairless. More than that, however, their thin, short legs allow them to move equally quickly forward and backward; their protuberant teeth assist them in digging; and their lips seal behind the teeth to ensure that their mouths stay free of dirt while they work.
As a reader, you will notice that by the time you finish this collection of sentences you have, as it were, settled in. You have received interesting, specific information, delivered clearly; you can now see the naked mole rat in your mind (except you can’t, and you should be thankful, because those suckers are ugly – there’s a picture of one in the back of this book). You’ve been engaged, and you’ve been relaxed. That is what the next few sentences of an introduction do: they make you feel at home.