In this question
God mentions that jews can eat gazelle and deers without sacrificing them first. That's because all sacrifice must be in the temple and once the temple is build it'll be too impractical to go to (or fly to/wait till rebuilding of) the temple first to sacrifice every time a jew wants to eat steak.
Here God uses gazelle and deers as samples. You don't sacrifice them, but you can eat them because they are kosher.
However, even though gazelle and deers are kosher, jews don't hunt anyway and hence, jews at that time most likely don't eat gazelle and deers per question Can Jews eat hunted animals?
So why God pick deer and gazelle as samples because jews don't eat them anyway.
Here, I presume that deer and gazelle are hunted animals. They may be trapped but that's more of theoretical possibility.