"rodents that ‘specialise’"

Nature The University of Liverpool have a theory as to why rats and mice predominate over other rodents. Their mouths are multi-functional:

"Scientists at the University have found that mice and rats have evolved to gnaw with their front teeth and chew with their back teeth more successfully than rodents that ‘specialise’ in one or other of these biting mechanisms.

"Researchers designed a computer model to simulate the bite of rats to understand whether their skull shape or muscle arrangement was a major factor in their evolutionary success and global dominance, making them one of the most common pest species in the world."

Unfortunately this has translated into humanity as jobs that were once done by three people now being offered to one.