The death of a gorilla at the zoo at Jersey has badly affected the remaining primates, staff have said.
Test results are expected to show death was caused by a virus
Ya Pili, a four-year-old western lowland gorilla, died 10 days ago from what is believed to have been a viral infection.
Durrell Wildlife Conservation Trust said gorillas were very family-orientated and the gorillas had been showing signs of mourning.
Staff said the band keep searching the enclosure for Ya Pili.
The results of a post-mortem examination will be shared with colleagues around the world who support gorilla conservation.
The zoo was founded by author and naturalist Gerald Durrell nearly 50 years ago.