Let's Read: Traveller, 1977 Edition, Worlds & Adventures, page 26

We continue with more alien animal info. On the last page, we were informed that if an animal takes twice its maximum damage, it's worthless for food or pelts; basically, it's a rabbit shot with a high-powered sniper rifle at point-blank range. So, the way you figure out how many hits it can actually take is simple: The animal size and weaponry will give a range, such as 2D/2D. That means that you roll two dice and add them together to get the number of points the critter can take before being unconscious. Then you roll two more dice, and add that total to the first total to get the amount of damage needed to actually kill the target. Twice that second number means it's a smear on the ground. Got it?

There are also modifiers for damage done by the alien animal, depending on its size. I don't have this table yet; the table I have is the terrain DM chart for encounter type and size. There are a lot of terrains here, too: Clear/Road, Plain/Prairie, Desert, Hills, Mountain, Forest, Woods, Jungle, Rainforest...

Wait. What's the difference between a jungle and a rainforest? I'm sure that some professional botanist will be able to point out exactly how those two differ, but let's be honest: They're the same thing. I mean, swamp and marsh got put together into one column, as did plain and prairie. But the rainforest is so special it has to have its own category. The table just gives DMs for the roll for animal type and the roll for animal's size.

Moving along, then. Animals get natural weaponry, such as fangs, claws, horns, maybe an armored plate like a triceratops. Some of the natural weapons are categorized by their similarity to a man-made weapon, such as a pike. And of course, there's a roll for that, too.

Then there's a Common Sense paragraph, capitalized and everything. And it is pretty common sense, although I have no doubt someone managed to completely miss those warnings and did weird stuff like have a neo-elephant wandering around on a world with a trace atmosphere. Don't do that. And don't have a big flyer on a 100% water world, because that would be impossible to sustain. In that spirit, change any rolls that make zero sense. But try to leave the rest alone, if you can, because it's that randomness that makes an alien world so interesting.

Finally, we get a paragraph on using the encounter tables. Basically, you roll once, or maybe more often, a single die. On a 5 or 6, there's an animal encounter waiting to happen. And, as always, the referee can modify the roll as needed, such as cover in the jungle.