Crocodiles 🐊, alligators, etc would cannot be seen in heaven because there would be be no more of them in heaven
Some wrong teachings even teach that because Jesus Christ carry animal in a picture now mean that animals would go to heaven of which Bibe is not in support of any Bible verse
Apostle John that saw this revelation did not tell us that there would be pet in Heaven, what he saw is the book of revelation
The only thing he saw is in revelation 21
Revelation 21:3-4 And I heard a great voice out of heaven saying, Behold, the tabernacle of God is with men, and he will dwell with them, and they shall be his people, and God himself shall be with them, and be their God.
And God shall wipe away all tears from their eyes; and there shall be no more death, neither sorrow, nor crying, neither shall there be any more pain: for the former things are passed away.
What he saw is people with God and God with his people
God command Paul to write about he saw, he did and didn't write what he didn't see at all
Revelation 22:18-19 For I testify unto every man that heareth the words of the prophecy of this book, If any man shall add unto these things, God shall add unto him the plagues that are written in this book:
And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and from the things which are written in this book.
Bible verses source; http://play.google.com/store/apps/details?id=bible.kingjamesbiblelite