Easiest way (be aware, I did say it's the easiest, didn't say faststest 😅😅) to farm literally everything animal based, including cementing past), plus pretty good loot, like arrows, metal hatchet and so on

1rst step tame two

2nd go on the southern cave

-Set them to agressive

-After each room, check levels & hp points

-Empty their inventory, to get the loots from everything they'd kill

-ride the one with highest xp

3rd Once they're both with 1000xp, go breed them

4 start over to step 2, with three frogs

Once every one's got 3000xp, breed them again, and kill one of the parents

-Restart over and over, as the breeds would get 4000xp each

At some point (when you'd see that their hp doesn't go below 10-20%, for ex.)

Do the same steps, all over, with the 3 frogs, at the next cave, to get more xp, and better loots (not the lava one, unless you'd kee the ones you're not riding at the entrance, obviously)

Then, finally, once you got the gas mask, or whatever to breath from the swamp cave, process same way at this one

Obviously, you cane replace any cave with the swamps, or even the herbivores/carnivorous islands

Again, I did say it's the easiest way, not the fastest

Because once the frogs would be well imprinted enough, they would be able to take on their own the toughest creatures, and you'd just have to check their inventory, from time to time