What does Hippopotamus look like on Google?

On Google it is the design shipped in 17.0, shown above at full size. Older revisions are listed beneath it.

When did Google add Hippopotamus?

Google first drew Hippopotamus in Android 9.0, released August 6, 2018.

Google LLC has shipped 13 versions of Hippopotamus. Each is dated, so you can see when the design changed.

Google Android 9.0

Google shipped a new design for Hippopotamus in Android 9.0, released August 6, 2018. The previous design is shown beside it.

The first Google release we hold for this emoji.

✳ marks a release that redrew this emoji. The rest re-shipped the design unchanged.

What does Hippopotamus look like on Google?: On Google it is the design shipped in 17.0, shown above at full size. Older revisions are listed beneath it.
When did Google add Hippopotamus?: Google first drew Hippopotamus in Android 9.0, released August 6, 2018.
How many times has Google redrawn Hippopotamus?: Google LLC has shipped 13 versions of Hippopotamus. Each is dated, so you can see when the design changed.