Poison-resistant rats discovered in East Yorkshire
1 January 2013 Last updated at 15:04 GMT
A breed of poison-resistant rats have been discovered in East Yorkshire by university scientists.
The so-called "super rats" appear to be genetically protected against the current range of poisons.
Researchers at the University of Huddersfield are investigating the animal's DNA to discover the reason for their immunity.
Look North's Phil Connell reports.