Going for a lvl 70 on hard mode with crops? Get fkn ready. Torpor drains hella fast. Almost 200 bio toxins used already and taming is still at 15%. You use 25 bio toxins on this guy, get back to it in a minute cause torpor bar will be draining already.
The method I used to tame was picking up the beaver with my crystal wyvern and dropping it in a taming pen. Pretty easy knockouts but their torpor drop rate is INSANITY and you can't leave then for more than 3 minutes. Feed them either mejoberries or crops (kibble is really expensive but if you want to do that, go for it).