Midway through 1974 (I'm not sure exactly when but the Forward is dated to July) TSR published Warriors of Mars, a set of miniature wargame rules based on Edgar Rice Burroughs' John Carter novels. There was only ever one print run, though, because the Burroughs estate was very quick to let TSR know that they were infringing on their IP rights. Consequently this book is very rare, but because the internet is awesome it can be found at archive.org, which is how I've been able to read a copy.
The game was written by Gary Gygax and Brian Blume, and not surprisingly it bears some resemblance to Chainmail. It covers large-scale combat with figures representing 50 men, and smaller conflicts where a figure represents one man. There are also rules for aerial warfare, and notes on many of the various characters and weird alien creatures from the books.
As for why I'm covering it, there are a bunch of references to Barsoom, the setting of these books, in the first D&D boxed set. Most notably these come in the Wilderness Wandering Monster tables, where a decent variety of Barsoomian creatures are given as optional encounter possibilities. None of them were given stats in D&D, so I thought I'd scour Warriors of Mars to see if I can get some guidance on the matter.
Before I start, these are the creatures I'll want stats for:
Red, Black, Yellow and White Martians (all basically human-like)
Tharks (Green Martians)
Apts
Banths
Thoats
Calots
White Apes
Orluks
Sith
Darseen
The first bit of good news is that Warriors of Mars has movement rates that are given in inches, and seem to be comparable to those used in Chainmail/D&D. I've reproduced the table below:
That covers movement rates for all of the creatures on the D&D tables. With humans moving at 12" the scale seems to be identical, so I can use these numbers as is.
Things get a bit harder when working out combat stats, though, because the combat in Warriors of Mars doesn't use the same system as Chainmail or D&D. It's much more chart-based, which makes it difficult to draw comparisons. The chart below, showing the combat ability of various characters and troop types, is helpful though.
The people of Barsoom are definitely hardier and more warlike than those of Earth, so using the scale above I think it's fair to equate the above numbers to D&D levels/Hit Dice. They serve a similar function in Warriors of Mars, being both combat ability as well as the number of hits a figure can take before being killed. John Carter would thus be a 13th level fighter, pretty much at the top of the scale for OD&D, but that's a fair assessment for someone described as the finest swordsman of two worlds. Red, Black, Yellow and White Martians would all have Hit Dice based on their individual skill level and the chart above. I guess most of their warriors would be in the 3-5 HD range, with leaders and elite guards ranging from 6 HD up to 10 HD. 11 HD and over seems to be reserved for the super-badass characters from the books.
That brings me to the table used for when someone is fighting a Barsoomian monster.
Most of those numbers are irrelevant for my purposes, but on the far left of the chart there's a column for "Wounds to Kill". This is pretty much the same rating as the one used for men above, so I'm happy to use it to calculate Hit Dice for the various Martian animals in D&D.
And so, here are the stats I gleaned for each one (not including the men, who are going to vary greatly):
Tharks
Green martians with four arms that live in tribes.
Movement: 12"
Hit Dice: 6
Apts
Tusked, six-limbed beasts of the frozen north pole region.
Movement: 12"
Hit Dice: 6
Banths
Lion-like beasts with ten legs.
Movement: 15"
Hit Dice: 7
Thoats
Horse-like creatures with eight legs.
Movement: 21"
Hit Dice: 5
Calots
Dog-like creatures with ten legs
Movement: 24"
Hit Dice: 5
White Apes
Semi-intelligent four-armed apes that inhabit the wilds and ruined cities.
Movement: 12"
Hit Dice: 6
Orluks
Described in this game as being similar to a jaguar, but in the Barsoom wiki as "elephantine".
Movement: 12"
Hit Dice: 4
Sith
Large predatory insects
Movement: 9"/30" flying
Hit Dice: 10
Darseen
A whole range of Barsoomian lizards, with these stats referring to the giant variety.
Movement: 9"
Hit Dice: 4
It's only two stats, with no Armor Class or damage or anything else, but for OD&D purposes Movement and Hit Dice are enough to go on. Everything in OD&D does 1d6 damage, and AC can be worked out by comparing to similar D&D monsters. This will all be handy for future reference, should PCs in my campaign ever end up on the red planet.