Risks associated with environmental enrichment: intestinal obstruction caused by foraging substrate.

Questions are occasionally asked about the safety of enrichment techniques, considering that many novel ways are frequently employed to ensure environmental complexity. A juvenile male vervet monkey was found with a phytobezoar of straw obstructing the sigmoid colon. The straw was foraging substrate, which is used in communal cages. Due to the extent of the resulting necrosis in the sigmoid and descending colon, the monkey had to be killed. This is the only individual to have suffered a harmful effect from the foraging substrate from amongst 120 vervet monkeys, which have been permanently housed on straw for over 5 years.