"We had our vet team on site immediately but sadly there was nothing that they could do for Misha", Jermey said.
The fire broke out shortly after 6am (local time) at the zoo's Animal Adventure section before spreading to the shop and cafe, near to an area where visitors can handle and feed animals, the zoo and London Fire Brigade said.
The fire brigade said it had sent 10 fire engines and 72 firefighters to the scene and added that the cause of the blaze was under investigation.
The zoo has confirmed it will reopen on Christmas Eve after earlier saying the attraction would be closed "until further notice".
A spokeswoman for the LFB said: 'Approximately half of an adventure cafe and shop, which also contains an animal petting area, is now alight.
TV footage from the scene showed the Adventure Cafe and shop to be badly damaged.
On Saturday morning, a massive fire broke out at the ZSL London Zoo.
A statement said: "Fire crews from Kentish Town, Paddington, Euston, West Hampstead and other surrounding fire stations are at the scene. We will update as quickly as the situation allows".
Security guards, along with zoo keepers who live on site, first responded to the fire, alerting authorities and moving the animals to safe locations within their enclosures, the zoo said. "The zoo with be open tomorrow, Sunday 24 December, from 10am".
'It is not believed any animals are involved at this stage'.
The cause of the fire is not yet known.
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