Rats and mice used for cancer tests in the US may soon have a diet regimen. Studies show that modern lab rats are about 25 per cent heavier than their ancestors were 20 years ago, which has caused a rise in the natural incidence of mammary and pituitary tumours, interfering with experimental results (Science, Vol 264, No 5163).
A way out of this peculiar problem is reducing the rodents' calorie intake by 10 per cent. Toxicologists feel, however, that a better method would be to replace obese rodents by animals bred for a slower growth rate and reproduce late in life.
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[1] http://admin.indiaenvironmentportal.org.in/news/rats-0
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/down-earth
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/rodents
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/science-and-technology
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/united-states-america-us