This probably doesn't fit in totally well here... but thought I'd put it here anyways
I recall when I was younger it was my 'life's goal' for the time to have seen at least one animal for each letter of the alphabet. I think it was an organisational thing. And so regardless of how common quails, yaks and newts were in relation to alligators, bears and camels, their relative monopoly over their respective letters got them some sort of special priority.
Only when I got older did the idea fall apart somewhat... in that the English language is only one way of referring to the different creatures of this Earth. And many animals will 'begin' differently in other languages....and some animals are called different things... if I see Puma concolor, then is that a 'P' animal for Puma or a 'C' animal for Cougar? Do I have to download the latest mammalology document to see which common name is preferred? And sure, Xenarthra works well as an entry for 'X' in absence of almost everything else... but then does that make every elephant and hyrax in the zoo an 'A' for Afrotheria? Does the taxonomy trick only work for lesser-used letters? Is a Burmese Python a 'B' animal or a 'P' animal? If an old text renders ‘zebu’ as ‘xebu’ then does that count? Or does the name of choice have to be listed in the dictionary?.....