Weick, B. G., Perkins, S. E., Burnett, D. E. et al. 1991. Environmental enrichment objects and singly housed rhesus monkeys: Individual preferences and the restoration of novelty. Contemporary Topics in Laboratory Animal Science 30(5), 18 (Abstract).

We found that the extent of physical contact with the [Kong toy, Nylabone ring and Nylabone ball] toys habituated during a short time. ... The introduction of a different toy every Monday was accompanied by a restoration of the apparent novelty of the toys.

Year

1991