Why do you suppose that is? Is it because God only revealed what was necessary and germane?
I so think that God revealed what was necessary. There isn’t enough room in the Bible to name every animal and really no reason for it. Sometimes it was necessary to mention the mundane and sometimes the extraordinary. This is one of the reasons I believe that the description in Job 40 is a dinosaur. They were some of the most majestic creatures every created (chief of the ways of God). Have a great day!