User blog comment:Justvisitin/Dino fusion history/@comment-5220945-20120707165114/@comment-5222017-20120707173037

Right. With the very limited data available so far, my best guess would be that species selection in fusion works similarly to species selection in the random option in the den: each species has a probability of being picked; the probabilities are just different for the den and the fusion. E.g., the cheapest “rare” dinos, protoceratops and dimetrodon, appear to have a very low probability of being obtained through fusion. Perhaps 0, perhaps, 0.0n. Everything else is too soon to tell, IMHO. Sure, brotornis appears to ocur deceptively often as a result of certain dino combinations, but it appears quite often, period. Any correlation with specific combinations may be entirely coincedental.

A random species selection would also make more sense both in terms of software design (the logic is already there for the den, why build another, difficult-to-maintain logic for the fusion?) as well as gameplay – random fusion results are simply more exciting and suspensful.