Comet, a 30-year-old European brown bear, a popular attraction at Camperdown wildlife centre in Dundee, died after being diagnosed with a tumour in his abdomen.
The animal was diagnosed last week and his condition deteriorated rapidly over the weekend.
Comet arrived at the centre from Edinburgh Zoo when he was 16-months-old.
Wildlife centre manager Aileen Whitelaw said: “Comet has been an important ambassador for Camperdown Wildlife Centre for almost 30 years and will be sorely missed.”
European brown bears are close relatives of the American grizzly bear and are of similar size, with an average life expectancy of 25 in the wild.
The mammals are mostly found in Spain, Italy and Romania.