7 days
edit(KP)
Part 1: put any 2 animals in the breeding den... BUT since...
Part 2: hatch a solar simian you can save time by putting in fire & nature, which I did not know
Part 3
Feed Solar Simian 50 times.
Part 4
Collect Prickly Pear Cactus (240 I think) - From Harvesting Crops.
I believe that's the last step.
I guess I'm glad I did not get that 45 hour breeding!