Saying they had exhausted every possible line of scientific inquiry into the various species, the nations researchers announced Thursday that they were completely done with rodents. Weve spent many decades and billions of dollars observing, testing, and recording every conceivable cognitive and behavioral aspect of hamsters, mice, rats, and basically the entire order Rodentia, so at this point were pretty much all set rodent-wise, said University of California biologist Emma Meuer, explaining that there was only so much that could be learned about the dietary preferences, spatial abilities, and decision-making skills of these small mammals before scientists started shrugging their shoulders and running out of new studies to subject them to. Weve learned how rodents process pain, how they gain weight, how theyll react to environmental stimuli, and on and on. To be honest, theyre not even that complex of organisms; weve kind of knocked out all there is to know about them. So, in terms of us and rodents, thats pretty much it. Meuer went on to note that the millions of lab rats at the nations universities and research facilities would be replaced in the months ahead by more interesting species that scientists said they would never tire of studying, such as lemurs and sharks. 