Cruel
Even though they knew that Ark was there, they didn't immediately attack him or anything, they just stared at him wickedly for a while. Ark did the same, he just stared at them, some residual anger shone in his eyes as he watched them, but he didn't do anything rash. Ark had nothing against killing other animals for survivals, but exterminating races just for the fun of it, that was actually messed up. Just a single race going extinct in his old world could seriously affect the ecosystem, even more so in a world like this.