He wanted to they know that, when they are older, they can no longer be bullied at will.
"Let him go! After defeating me, you can talk about teaching me a lesson." Mateo took off his equipment. Although he carried the small knife given by Clara, he wasn't foolish enough to engage in close combat. Dealing with these old beasts required using force against force. Whoever is crueler than the other will win, and the loser had to obey the winner.
In the rain forest, it is pitch black, and the beast's eyes can see in the dark night. To them, such a dark night is no different from the day, just that it lacks color.
Mateo directly faced Jack, who was in his fifties but still in his prime. In Jack's eyes, Mateo was nothing more than a hairless baby.
Beasts considered life truly beginning after the age of fifty, and physical strength was at its peak during this period.