S-11 is an update to the old Classic Traveller S-2 (Also called "Animal Encounters") and follows a broadly similar format. The old book was essentially GDW going ahead and creating Animal Encounter tables for you for all of their possible environments. S-2 was a time saver, but didn't really introduce anything new to the rules. In fact, you neeeded Book-3 to interpret the tables.
S-11 goes well beyond that by including a few pages that expand the core rulebook's animal creation system fairly significantly, and give a Referee quite a toolbox for coming up with interesting and varied animals for his players to shoot.
I haven't tried the system yet, but it seems workable (if a little confusing in some spots) and looks to generate interesting animals.
The bulk of the book (like in the original CT S-2) is a comprehensive set of encounter tables for worlds of varying size, temperature and atmosphere. Adding temperature is a nice touch here, as I don't recall it in the original. There are quite a few tables here, each of which has 11 unique encounters (10 animals and 1 "special event", generated with 2D6), as well as a target number (again, on 2d6) for how likely an encounter is in that environment. Interestingly, gas giants and outer space are two of the environments catered to, if you run a more space-operatic game. Unlike CT S-2, the outer space table isn't "rocks and radiation", it's weird alien animals.
These tables are packed densely with information, and give you (almost) enough information for a casual encounter with the critters mentioned. Not all of the random events will be useful to all styles of play, but it's easy enough to come up with something else if you don't like the listed effect.
I still don't like the fact that the animal's weapon and armor type are just for description (horns and teeth do the same damage as claws on the same sized animal), but with the MGT armor system, there isn't a lot of option. C'est la vie.
My only complaint with the book (and it's unfortunately not a trivial complaint) is about what they did NOT include in the encounter tables - the animal's size and movement method. You can't tell at a glance how large the creature is (though you can partly infer it from the listed size dice) and there is no way to know if the creature flies, runs, swims, etc. In Mongoose's defense, doubling the lines to provide some of this information would have made the book much too large, so I understand the trade off, even if I don't like it. I would have rather had them not pre-roll the stats, which are all specified as "##(#d6)" so you know both the value and the dice used to get the value.
For anyone who needs to come up with some generic animal encounters for a safari or crash-landing, these tables could be a godsend. I would suggest that if you have time, you should go through the tables for the world/terrain your players are visiting and make a few notes about the animals in the table.
Finally, they have a few fully-worked up animals, complete with stats, skills, habitats, text write-up, etc. These are fully playable animals (aside from not mentioning their size again, inexplicably!) and ready to drop into a game directly. Also included are some good notes on how to modify the given animals for a variety of different climates. And of course, there is an "animal character sheet" at the end, so you can record your creations.
Final Thoughts:
Ever since MGT Core Rules introduced the new way of doing animals (and invalidated the old CT animal system in the process) I've been looking for this book. With the exception of the authors apparently forgetting about Animal mass and movement type, this book meets my needs. I have a TON of tables for running random safari encounters and a system for generating "main character" animals that rivals the Sentient Character generation system.
One of the first projects I'm going to undertake is to make a reference sheet to help interpret the tables - possible sizes for each Strength dice, base skills of each behavior type, etc. It seems that it should be possible to make a one (or at most two) sided reference sheet that would help smooth over the missing information (skills, size, etc.) and make running animal encounters with the random encounter tables a joy. If I manage to make such a table I will of course share it.
S-11 goes well beyond that by including a few pages that expand the core rulebook's animal creation system fairly significantly, and give a Referee quite a toolbox for coming up with interesting and varied animals for his players to shoot.

The bulk of the book (like in the original CT S-2) is a comprehensive set of encounter tables for worlds of varying size, temperature and atmosphere. Adding temperature is a nice touch here, as I don't recall it in the original. There are quite a few tables here, each of which has 11 unique encounters (10 animals and 1 "special event", generated with 2D6), as well as a target number (again, on 2d6) for how likely an encounter is in that environment. Interestingly, gas giants and outer space are two of the environments catered to, if you run a more space-operatic game. Unlike CT S-2, the outer space table isn't "rocks and radiation", it's weird alien animals.
These tables are packed densely with information, and give you (almost) enough information for a casual encounter with the critters mentioned. Not all of the random events will be useful to all styles of play, but it's easy enough to come up with something else if you don't like the listed effect.
I still don't like the fact that the animal's weapon and armor type are just for description (horns and teeth do the same damage as claws on the same sized animal), but with the MGT armor system, there isn't a lot of option. C'est la vie.
My only complaint with the book (and it's unfortunately not a trivial complaint) is about what they did NOT include in the encounter tables - the animal's size and movement method. You can't tell at a glance how large the creature is (though you can partly infer it from the listed size dice) and there is no way to know if the creature flies, runs, swims, etc. In Mongoose's defense, doubling the lines to provide some of this information would have made the book much too large, so I understand the trade off, even if I don't like it. I would have rather had them not pre-roll the stats, which are all specified as "##(#d6)" so you know both the value and the dice used to get the value.
For anyone who needs to come up with some generic animal encounters for a safari or crash-landing, these tables could be a godsend. I would suggest that if you have time, you should go through the tables for the world/terrain your players are visiting and make a few notes about the animals in the table.
Finally, they have a few fully-worked up animals, complete with stats, skills, habitats, text write-up, etc. These are fully playable animals (aside from not mentioning their size again, inexplicably!) and ready to drop into a game directly. Also included are some good notes on how to modify the given animals for a variety of different climates. And of course, there is an "animal character sheet" at the end, so you can record your creations.
Final Thoughts:
Ever since MGT Core Rules introduced the new way of doing animals (and invalidated the old CT animal system in the process) I've been looking for this book. With the exception of the authors apparently forgetting about Animal mass and movement type, this book meets my needs. I have a TON of tables for running random safari encounters and a system for generating "main character" animals that rivals the Sentient Character generation system.
One of the first projects I'm going to undertake is to make a reference sheet to help interpret the tables - possible sizes for each Strength dice, base skills of each behavior type, etc. It seems that it should be possible to make a one (or at most two) sided reference sheet that would help smooth over the missing information (skills, size, etc.) and make running animal encounters with the random encounter tables a joy. If I manage to make such a table I will of course share it.