Keepers Diary - July 2008
The most important role of a zoo keeper is looking after the animals they care for. This involves feeding, cleaning out, noticing and getting any illnesses treated and also keeping the animals busy.
This keeping busy is known as ‘enrichment’ and can be as important as anything else in maintaining the animal’s health.
If an animal is kept busy and its mind active, it is much more likely to resist illness, in a similar way to humans and the link between stress and the immune system. There are many types of enrichment, including modifying an animal's enclosure or environmental enrichment, as discussed in last month’s zoo diary.
Another is operant conditioning or goal based training, like I carried out with the sloth bears and discussed in the August 2007 zoo diary. Yet another type, and probably the most fun from a keeping perspective, is making enrichment devices.
The aim is to provide the animal with a mental or physical challenge that keeps the animal busy, as well as leading the animal to exhibit behaviours that would be exercised in the natural environment.
That may involve food rewards, as most of what animals do in the wild is centred on an aim to get food. It is very challenging coming up with new ideas sometimes, but it is essential not to repeat the devices too frequently - otherwise they lose their impact.
Each device must also be gauged in terms of difficulty for the specific species it is to be used for. Too easy and the enrichment will be over too quick, but too difficult and the animal may not be able to get the food and therefore give up on the idea.
Furthermore, a lot is dependent on the personality of the species or individual animal. An agouti is a lot less interested in enrichment and will only use food based devices, whereas a pig or a meerkat will investigate anything, even if it is just a bucket of their old poo!
Recently, I made bamboo feeders for the ring-tailed lemurs, where they had to pull out a number of sticks to release grapes from the hollow bamboo tube. These kept the group busy for over a hour, mainly due to the lemurs not being the sharpest of animals! (I used a similar enrichment device with large monkey species and it was over in a flash.)
Another great enrichment device used with the aye ayes involves logs with drilled out holes filled with wax worms. The holes are then filled in with pieces of broom handle so that it is impossible for us to even get them open.
This demands a very natural behaviour from the aye ayes. They use their rodent-like teeth to bite out the broom handle pieces, just like they would do to the bark of a tree to get at the grubs inside. They then use their hook-like long finger to grab the succulent worms out and enjoy their much deserved reward.