Beast portal mobs

I've probably played 4+ hours a day since launch of this league and have yet to find 1 portal beast, been doing nothing then running tier 13+ maps for the last 2 weeks......they don't exist? or am i just the most unlucky when it comes to these. lol

I've played quite a bit this league and found a crab and avian. They exist but I guess they are very, very, rare.