Certainly not the easiest mob to solo thanks to Plenilune Embrace spamming (heals upto 2000 HP & erases debuffs) and their insane attack speed. Trio'd 30 or so with TH3 last night and didn't see a single claw drop.
Highly suggested to bring a thief for at least Treasure Hunter 2 while fighting these. With Treasure Hunter, you can average approximately 1 claw per half hour. About one claw every four to six hours without.
The droprate is extremely low. Yesterday in Batallia, I got 2 drops out of 65~ kills (solo, TH4). The fights can be fairly long, because of the healing TP move, Plenilune Embrace. I estimated their HP to be about 5000.