The family of four were treated to a special papier-mache turkey, covered in honey and filled with prawns for them to discover.

Keeper Linda Matthews said the Christmas enrichment program was designed to encourage natural behaviour such as foraging and problem solving.

"Anytime the keepers have time they try to do it. If it's a special time of year we try and make it that theme, so at Easter time we make something to do with Easter," Ms Matthews said.

She said the otters use their front feet to get their food, so the enrichment program builds their hand-dexterity.

The two young otters, who will be one-year-old in January, where the most curious about their treat, quickly followed by mum and dad.

While the treats inside the turkey were fun for the otters, Ms Matthews said they would play with the papier-mache as well.

The Siamang Apes were also treated with coloured candy canes and frozen ice blocks filled with fruit.