<- Back to all case studies

Marmosets Harmed in Neuroscience Experiments

Summary:

• 11 marmosets (a type of small monkey) had holes drilled in their skulls and a substance injected into their brains,
• The animals also underwent surgery to have probes inserted into their hearts to measure their blood pressure at certain times,
• They were observed being stared at by a person they did not know (‘intruder’) and also when they were expecting a reward and their behaviour noted,
• Later on they had two cannula inserted into different parts of their brains and these remained in place, being cleaned each week,
• Substances were injected into the cannulas to reach the different parts of the animals’ brains,
• The animals were again observed with the ‘reward’ and the ‘intruder test’ to observe differences in their behaviour,
• At the end of the experiment, the monkeys were killed, their brains removed and thinly sliced so they could be analysed.

The researchers describe how the marmosets were housed in ‘male-female pairs’ in cages which were 2.8 x 1.2 x .98 m. This information shows how unnatural life in a laboratory is for these animals. They originally come from Brazil and in the wild they would live in groups of up to 20 individuals and have a home range of between one and 16 acres (an acre is about half the size of a typical football pitch)

In the wild the animals can live as they like, typically they would be more active in early morning and the later evening. Around midday, they will nap and groom a lot. At night the group would sleep together in a tangle of vines or on a tree branch.