This involves testing a substance on a pregnant animals to see if birth defects occur. The drug Thalidomide does not cause birth defects in guinea pigs, rats or mice. However, it has devastating consequences when taken by pregnant women. Mice, rats, rabbits, birds and fish are usually used but dogs, cats and monkeys have also been used. Scientists study animals for convulsions, tears, diarrhoea, discharge and bleeding from the eyes and mouth.
Unusual vocalization are typical symptoms in dying animals.
Skin Irritancy Test Substances are applied to the abrased skin of animals but there is considerable variability between species. The greatest differences are found with the more irritant substances. For example, an anti-dandruff shampoo caused severe irritation in rabbits, mild irritation in human volunteers and virtually no irritation in baboons. Scientists' main defence for using animals in experiments has been to stress the health benefits to humans from such research. However critical assessments of various fields of animal research have revealed that claims of health benefits are grossly exaggerated.