Sumatran tiger cub Loki dies following seizures at London Zoo

Following four seizures, each worse than the last, vets euthanised Loki on February 24.

Sharing the news on the ZSL website, chief operating officer Kathryn England said: "Being responsible for an animal’s welfare, means sometimes making decisions that break your heart. But we know we made the right one.

To mark the Chinese Year of the Tiger, ZSL London Zoo has shared stunning images of baby tiger cub Loki and mum Gaysha The seven-week-old Critically Endangered Sumatran tiger – named Loki by the international conservation charity’s members in an online vote - has also now been confirmed to be male by the Zoo’s tiger keepers. (Image: ZSL/George Cuevas)

"We had all fallen in love with little Loki and know that many of you had too. We wish we had different news for you but are so comforted by the outpouring of kindness and compassion you’ve shown us already this week."

A post mortem is being carried out with results expected next week.

Loki was born on December 12 to mum Gaysha and dad Asim.

One of an original litter of three, the cub’s two siblings sadly did not survive labour.

To mark the Chinese Year of the Tiger, ZSL London Zoo has shared stunning images of baby tiger cub Loki and mum Gaysha The seven-week-old Critically Endangered Sumatran tiger – named Loki by the international conservation charity’s members in an online vote - has also now been confirmed to be male by the Zoo’s tiger keepers. (Image: ZSL/George Cuevas)

Ms England said Loki suffered his first seizure on February 18 and was rushed to the veterinary hospital for medication.

Treatment stopped the first seizure but he needed medication for lethargy which appeared to perk him up.

As plans were made to take him to the Royal Veterinary College, in Camden, the cub had two more seizures.

"Once again there was no obvious cause – in fact he had spent a peaceful Sunday snuggled up with Gaysha," Ms England added.

Loki had emergency MRI, CT scan and multiple blood tests as well as a spinal tap.

"We left no stone unturned. Through our tests we ruled out so many things; a brain tumour, infections, parasites – frustratingly we still had no answers.

" We were considering a presumptive diagnosis of epilepsy – something that can only be confirmed through a process of eliminating all other possibilities."

His condition seemed to improve by the Thursday (February 24) when he enjoyed a calm morning playing outside with his dad.

To mark the Chinese Year of the Tiger, ZSL London Zoo has shared stunning images of baby tiger cub Loki and mum Gaysha The seven-week-old Critically Endangered Sumatran tiger – named Loki by the international conservation charity’s members in an online vote - has also now been confirmed to be male by the Zoo’s tiger keepers. (Image: ZSL/George Cuevas)

"Devastatingly, Loki then had another seizure," she said. "Far more serious than those before, the seizure confirmed the vets’ worst fears; Loki’s fits were not going to stop and his health would only decline."

Ms England added: "We will of course continue our efforts to understand Loki’s condition."

The post mortem is being carried out "in the hope that we can help another tiger cub – and the future of this critically endangered species", she said.