A new species has been appeared at The Great Plume! This creature can be found while excavating, with its numbers being much greater than usual for the next week. Once it is no longer a guaranteed reward, it will appear at its normal rate.
Creatures acquired through Excavation go into either a free baby slot or a hold slot if you don't have one of the former free. If you don't have space for neither of these slot types, you won't be able to claim your rewards. The chance for creatures is independent of your chosen action and reward result—your odds increase only by participating in more rounds, resetting once you've acquired a creature as a reward.
If you're curious and would like to watch the new species mature before yours will, you're welcome to take a look down below.