Monkey keeper Andy Fry has also been trialling the aromatherapy. He said: 'We use scent-based enrichments and have had some good results. Monkeys respond to fruit scents like orange and lemon.
'However, we have never had such a wide range, so this is an excellent opportunity. It will be interesting to see what effect lavender and tea tree oil have.'
There is also a veterinary use for the oils. Ghislaine Sayers - the zoo's head of veterinary services, said: 'You can mix almond oil with water and spray it on pigs and primates with dry skin. If a monkey has a cold, you can nebulise olbas oil with water or put it on a wet towel somewhere where the animal can smell it but not reach it."
Paignton Zoo Environmental Park has won awards for its environmental enrichment work, which encourages natural behaviours and stimulates mental and physical activity.
Enrichment can include wind chimes, background music, balls, bubbles and CDs hung up to catch the light.
In the wild, animals walk miles in search of food or migrating with the seasons. In zoos they cannot.
A Paignton Zoo spokesman said: 'Environmental enrichment helps to replace these activities and occupy the time of animals such as primates, elephants and big cats.'