I try to keep track of my animals in a little ss. I use it to see which is the best value to upgrade. Last night I sent one to the evolution flower and when I put him back in my habitat today it appears he now makes FEWER coins per hour than he did at level 9! So I took a look at my other animals and the higher level ones ALL make less income. Some of them a LOT LOT LOT less:
A few examples:
Iciclaw: level 9 yesterday was 428/hour. Today level 10 is only 371!
Solar Simian level 10: was 378/hour, now 368. That is a low of 110 per hour.
Ancient Sloth level 9: was 835/hour, now 800.
Pandaffodil level 10: was 263/hour, now 212.