Five wolves have been put down at Camperdown Wildlife Centre in Dundee.
Bosses at the attraction made the announcement on Monday.
It followed an operation to the alpha male wolf Loki last week.
The centre shut last Wednesday to allow Loki to recover from his surgery and reopened on Thursday.
However, he was said to have suffered complications and had to be put to sleep – along with the four other wolves in his pack.
A statement on the Camperdown Wildlife Centre Facebook page said: “We are devastated to announce that our alpha male wolf, Loki, has been humanely euthanised today.
“Despite an initially successful operation, there have been subsequent complications, and the difficult decision was reached to save the animal from further pain.
“The other four wolves in the pack have been exhibiting unusually anxious and abnormal behaviour since the operation, and it is with great sadness that these wolves have also been euthanised as a result.
“This course of action was a last resort, and our team is absolutely heartbroken.
“We ask you for your kind consideration at this time.”
Locals have reacted with shock and sadness to the news.
Posting on social media in response to the announcement, one wrote: “So sad – the vets and team know what they’re doing so they must have had no choice but to euthanised the others.”
Calls for centre to explain decision
Another posted: “So sad, our thoughts are with all staff.”
Several others have urged the centre to clarify why other wolves had to be put down.
One wrote: “I’m so sorry to read this news and my thoughts are with all involved but if you wouldn’t mind could more of an explanation be given into why the four others were destroyed?
“This is heartbreaking to read and I can’t help but think the public should be given more information to help with understanding this dreadful news.”
One other poster added: “Can’t quite imagine what they were, and you now are, going through.
“We appreciate the love you give these animals and you must be absolutely devastated.”
Loki, a rare European Grey wolf, arrived at the zoo with female wolf Aurora in 2016, in the hope they would contribute to the European breeding programme to help reduce pressure on wild environments.
The pair quickly had two cubs just months after being released into their new enclosure before Aurora gave birth to five more cubs the following year.
