Hand-rearing and re-introduction of an infant gorilla (Gorilla gorilla gorilla) to his family group using an inexperienced female surrogate

In August 2020, Bristol Zoo’s gorilla keepers arrived in work to the wonderful site of a newborn gorilla infant. Over the first few weeks, mum Kala seemed to be coping well and the infant appeared strong. However, the next few weeks saw a severe deterioration in the infant, requiring keepers to intervene. Despite numerous attempts at keeping mother and infant together, in then end staff had to make the difficult decision to remove the infant for hand rearing. Over the next six months, the infant (named Hasani) was hand reared always with the goal of an early reintroduction back to his troop. Keepers prepared both him and the group for the reintroduction process and all that it entailed.

At almost seven months old, reintroduction to mum Kala was trialled. Attempts lasted several weeks and different methods were used to try and reunite the pair, however it was unsuccessful. Staff then looked to another female in the troop to act as a surrogate. This female, Kera, had no rearing experience of her own, but showed positive signs towards Hasani and staff were successful at getting Hasani back into the troop because of her nurturing, support and care.  

This award submission highlights all the decisions that led to the point of removing Hasani for hand rearing and the protocols that were put in place, particularly having to juggle the added risk of covid-19 transmission. It also detailed the reintroduction processes, for both mum and surrogate and the long and somewhat difficult process of re-building the troop around him.

This projected was submitted to the BIAZA Awards Behaviour and Welfare category 2022 and won a Gold award.