Rise of the super rat

Humans have been using the same rat poisons
since the 1950s, and scientists are concerned
that the rodents have developed a mutation that
makes them immune.
Reports this year suggest that rats in the UK are
also becoming bigger, with a new strain of 'super
rat' expected to outnumber humans by next year.
Scientist Dr Dougie Clarke explained that female
rats are able to breed again immediately after
giving birth to their young, meaning that they
multiply extremely quickly.
Rats are responsible for spreading bacteria,
viruses and diseases as well as inflicting damage
on buildings.