Edinburgh Zoo has come under fire for "ghoulish" plans to charge £20 for visitors to watch the autopsy of an animal.
The zoo's animal post-mortem examination is due to take place on August 23 in front of a live audience.
Zoo chiefs said a "large mammal" would be dissected but they were not sure yet what species it would be or where it would come from.
But the plan - coming on the back of months of controversy for the zoo - was described on Wednesday as a "callous money-spinner" by one campaign group.
The zoo's website is promoting the attraction as "a fascinating insight into animal biology", offering audience members the opportunity to "see at firsthand what the inner workings of a large mammal really look like".
A warning accompanies the advert that no one under 16 will be admitted.
Hugh Roberts, the new chief executive of the trust which runs the zoo, insisted the attraction would be of educational value.
He said: "Educating people about animal life cycles and behaviour is central to our work as a conservation body."
Through scientific events such as this, we can help promote this understanding."
A member of the zoo's world-renowned veterinary team will perform the autopsy, which is being organised to help members of the public learn about animal biology.
Last year, the zoo showed the autopsy of a cow before a live audience at Edinburgh International Science Festival last April, charging £11 per ticket.
More than 100 people emailed Science Festival director Simon Gage calling for the event to be scrapped following a campaign by several animal welfare charities.
A spokesman for the city charity OneKind said: "This seems a really staggering thing to do at a point when the zoo doesn't need to court any more controversy.
"It's sending out the entirely wrong message that these [animals] are exhibits that can be put out on display even when they're dead."
The spokesman said charging £20 a ticket would be widely seen as a money-making move as just two months ago the zoo published income losses or £2m.
He added: "The zoo makes great pains to highlight what an educational organisation it is, but this smacks of unwavering commercialism.
"I could understand possibly an educational aspect to host this for the public as a scientific demonstration, if it were free."
A spokeswoman for Peta - People for the Ethical Treatment of Animals - said: "Whilst the idea of paying to view the dissection of a cadaver may not sit well, what's truly disturbing is the unnatural and miserable life animals are forced to endure in confined zoo environments."
Labour MSP Elaine Murray called the proposed public autopsy "ghoulish".
She said: "It sounds like a Victorian thing. People have mixed feelings about zoos and this isn't going to help them feel kindly towards them. I know the zoo may have financial difficulties, but I don't think this is appropriate at all."