The Biology Unit is dedicated to the international cooperative study of biological postage stamps and related material.
The journal Biophilately covers new zoological and botanical stamp issues worldwide.
A very impressive topical collection of stamps depicting reptiles and amphibians, organized both
by species and by country, with distribution maps, etc.
This site contains over 800 scanned stamps, maxi cards and covers, but has been made as
"bandwidth friendly" as possible; only "thumbnail" images load automatically
so you can choose which large images you want to see, and the lists are broken into multiple pages
for faster loading.