To give you an idea of how out of touch with reality these academics are, I can tell you from firsthand experience working on demolition crews in New York city that I have lifted dead rats with rubber gloves that were three times the size of that gerbil the scientist is holding in that photo. Sewer rats in New York achieve sizes that boggle the mind. You could live there twenty years and never see them unless you've worked underground (as I have) or else you have been somewhere like the Bowling Green subway line after 3 am in the morning when the access gates have been locked and the lights turned out. The rats that come out on the platform that time of the morning when they think all the humans are gone would cause you to pee in your pants. My first impression when I woke up one morning in Bowling Green was that the platform was crawling with hundreds of hairy loaves of bread.
The biggest rat I have ever seen was taken from a derelict building by my supervisor in Brooklyn during a demolition job I worked out there after the exterminators had gassed the basement. The supervisor had to tie a rope around it's head to pull it up the stairs. It looked like a small Dachshund with stubby legs, gray fur and pink paws. This rat could have swallowed that one in the photo like a jelly bean.
Now imagine ten years after a nuclear war, the rats that might become common after emerging safely from their deep rock shelters with ten million or so human corpses to feed on and few natural predators. I expect you'll need a big gun to keep those kind of rodents tightened up.