Make a 1,1 to 3,3 stone dino gate sqare for each roll rat . Get a karkinos and put 1 or 2 in each pen and when you need gems just jump into the pen with the karkinos hold the roll rat/roll rats for around 1 minute to be sure let them go and they will borrow immediatly then wait for them to surface grab them again . You will have aprox 20 seconds to grab the gems before they disapeer so grab them . Now let the roll rats go and to reapeat this step you must run a certain distance way from the roll rats to stop them from aggroing .
Just a little heads up, this thing's saddle has a durability bar. Guess how I found out?
Visiting ab using this armored scrotum's magical ability to blackbox itself with wood in 2 minutes. Completely naked, no weapon, no other dino. Carelessly rolling down crab river at mach 6 and poof. Ejected me into the water to get mercilessly beaten to dust by 5 karkinos, two spinos, the liquid that seems to be made entirely of piranhas, and 3 sarcos.
Make an extra saddle or two if you take this thing out.
When tamed,the moment it receives damage it can attack back immediately,something like instant counter attack,which is very useful against a pack of dinos. Also its a version of Therizino on russian drugs for abberation,best wood gatherer.