In Biggest vs. Smallest, Susan K. Mitchell compares animals much like the birds- an ostrich  to a hummingbird. BUT Mitchell compares a Komodo dragon to a dwarf gecko, a Goliath frog to a Brazilian gold frog, and an anaconda to a Lesser Antillean threadsnake.  While I’ve known of Komodo dragons and anacondas for 30 or more years, this book is quite up-to-date since the dwarf gecko (which can fit on a dime) was only discovered in 2001 and the Lesser Antillean threadsnake (which is as thin as pencil lead and can fit on a quarter) was discovered in 2008.