This technique uses fewer animals and is designed so that none of them receive a fatal dose of the poison. Laboratory animals spend most of their lives simply living in the animal house and not being used in an experiment, so it is important to consider their living conditions. In the past, laboratory animals would often be kept alone in barren cages. These days we prefer to keep animals in social groups, preferably in large cages or floor pens, with things for them to play with. Rabbits would be given bedding material, boxes and tubes.
Rodents like to have nesting material.
Dogs like running in groups and having human company. Monkeys like branches to climb, swings, ropes and platforms. Their diet can also be made much more interesting with fruit and other titbits. Some of these can be mixed in with wood shavings so that they have to forage for their food - a favourite activity. See also our pages on animal welfare and regulation .