The baby boy was born overnight on August 24, with keepers arriving at work to see mother Jai doting over her newborn. This is the second baby for Jai and father Pedro, with their first baby Isadore born in October 2017.

"Jai was a natural mother first time around and is clearly still a calm mother taking caring for her second baby in her stride," primate keeper Sasha Brook said.

"We are really happy with the maternal behaviours Jai is displaying and because we have a good rapport with her we are able to get up close to check on the baby and how it is doing and we are very pleased to see him doing well."

Spider monkey babies cling on to their mothers with an amazing grip and suckle as needed for the first few months of their lives.

After three or four months the babies become more active and move to dorsal riding on the back of their mother and start exploring their surroundings a little more.

"Visitors to the zoo may find it difficult to see the new arrival at present as he is clinging to his mum's tummy however, when they move to dorsal riding they are easier to see," Ms Brook said.

"There are now six youngsters on the spider monkey island including the most recent baby born into the group and we are hopeful there is another baby on the way.

"It is really amazing to see the different ages in the group now and the watch the juveniles interact with the adults.

"Pedro is particularly good with the youngsters and is often observed playing with them."

The black-handed Spider Monkey conservation breeding program at Taronga Western Plains Zoo has now welcomed four females and two males since the arrival of Pedro the breeding male from France in 2014.

"Having another male born into the group is really exciting, it widens the genetic diversity in the group which benefits the regional conservation breeding program," Ms Brook said.

"One day once he is mature he may move to another zoo and sire babies of his own."