The Humane Society is raising doubts about animal care at the Greater Vancouver Zoo after the death of a young giraffe this week.

Three-year-old Amryn died Monday after he was found lying on the ground in his enclosure. A cause of death has yet to be determined.

Peter Fricker of the Vancouver Human Society says that tropical animals like giraffes shouldn't be raised in northern climates -- they need to be kept in heated barns and fed special diets that give them energy to stay warm.

"The big question we have for the Greater Vancouver Zoo is, was that baby warm enough over these past few cold days and was its diet appropriate for this climate?" Fricker told CTV News.

Cold weather has led to giraffe deaths in B.C. before. In 2009, it was identified as the cause of death for two giraffes at the Mountain View Conservation Centre in Langley.

But Greater Vancouver Zoo spokeswoman Jody Henderson says temperature isn't an issue in the giraffe enclosure.

"They have a heated indoor facility to go into, and that's where he was. His temperature was checked at the time and there was no problem with the temperature," she said.

She says Amryn was healthy and active before this week, but he was clearly suffering when staff members found him on Monday.

"He was on the ground -- giraffes don't usually stay on the ground for too long. He just wasn't himself. He was in a shock state," she said.

Animal welfare advocates say the zoo's problems go deeper than the death of one giraffe, though.

"They have a pretty poor record of animal care there, with a number of animals dying prematurely over the past few years," Fricker said.

In 2006, the SPCA pursued an animal cruelty charge against the facility, accusing the zoo of housing a hippopotamus named Hazina in an enclosure that was too small. The charge was stayed when the zoo agreed to upgrade the space.

Animal cruelty officials also investigated after the deaths of four zebras when two Cape buffalo were introduced into their enclosure in 2009.

The SPCA says it is not investigating the death of Amryn, but would like to see the animal's necropsy results. The young animal would have turned four next month.

With a report from CTV British Columbia's Lisa Rossington