As the old adage has it, cleanliness is next to godliness, but it also has sinister consequences for lab rats: they are much more likely to cannibalise their young if their cages are frequently cleaned.
Charlotte Burn at the University of Oxford and Georgia Mason at the University of Guelph in Ontario, Canada, found that nearly twice as many pups were eaten in cages cleaned twice a week as in those cleaned fortnightly (Applied Animal Behaviour Science, ). Cannibalism was most likely if the cages were cleaned soon after the pups were born.
Burn notes that cannibalism in rodents is not unusual; mothers sometimes eat unhealthy young to conserve energy for raising healthy ones. But while this might be normal behaviour, it could be disruptive in a research context
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The findings suggest that cleaning their cages disrupts the rats鈥� ability to recognise their kin, according to Volker Rudolf at Rice University in Houston, Texas. Burn says that scent is the key to rats being able to recognise their pups. She suggests minimising the handling of very young pups to avoid interfering with the scents that bond their parents to them.
It is also important, she says, to avoid introducing foreign scents into the rats鈥� cages. For example, lab technicians should avoid handling several rats one after another.
Finally, Burn advises, cleaning the rats鈥� cages should not 鈥渟tress the parents with loud noises or physical disturbance鈥�.
