Dolphins' Heroin Overdose Blamed For Deaths After Zoo Rave

Oft-cited as one of the most intelligent animals outside of humans, dolphins exhibit highly evolved behaviors -- vocal communication, group fishing, and juggling complicated social lives.

But overdosing on heroin?

That's a new one.

According to a report by The Daily Mail, two dolphins at Connyland Zoo in Lipperswil, Switzerland, died following a weekend-long rave held at the zoo with a heroin substitute coursing through their systems.

The Sun reports the two dolphins, Shadow and Chelmers, had ingested Buprenorphine, a drug often used to wean addicts off junk, likely given to them by clubbers during the rave.

Initial reports by The Daily Mail attributed the mammals' deaths to the pulsating music at the techno gathering. But a leaked toxicology report revealed the presence of the recreational drug in their systems, which, according to marine biologist Cornelis van Elk, presents a distinct danger because "dolphins are conscious breathers, which means they actively decide when to come to the surface to breathe," and that taking an opiate "causes this part of the brain to switch off."

According to The Sun, Shadow and Chelmers died slow, painful deaths. Shadow was found dead after the rave, while Chelmers "was drifting under the water" and "shaking all over and foaming at the mouth."

The Mirror notes trainers took Chelmers out of the water with his tongue hanging out, and administering adrenalin didn't improve his condition. The dolphin died after an hour.

"I have not been able to sleep since," zookeeper Nadja Gasser told The Sun.

Animal activists warned Connyland and local planners about the dangers of the rave before the event, according to The Daily Mail, concerned with how loud music would affect animals that use sonar.

The zoo has denied any wrongdoing.