In a move marking the end of legal options open to animal rights groups over Lucy the elephant – the Supreme Court of Canada has decided it will not hear their appeal.

The 36-year-old Asian elephant has been at the centre of controversy, after a handful of animal rights groups attempted to sue the City of Edmonton – in a bid to have Lucy moved to a warm-weather wildlife sanctuary in the U.S.

People for the Ethical Treatment of Animals (PETA), Zoocheck and Voice for Animals wanted to challenge an Alberta Court of Appeal split decision dating back to 2010 – which ruled against their plan to sue the city.

"I have to say we're disappointed for sure," Tove Reece with Voice for Animals said.

"Apparently the Supreme Court only hears about 10 per cent of applications."

The animal-rights groups believe Lucy should be moved to a warmer climate and a sanctuary with other elephants.

However, city officials have long defended the care Lucy has been getting at the Valley Zoo, and said her health problems are manageable, but the stress of a move would put her life in danger due to breathing problems.

"Everybody has their own opinion, and having a dialogue is never a bad thing," Dr. Milton Ness, veterinarian at the Valley Zoo said. "Either way, I'll be continuing to do what's best for Lucy."

One official told CTV News the attention put on Lucy recently has put a lot of stress on staff working with her, and they look forward to moving on.

"We continue to take Lucy's best interests to heart, and try to do what we believe is the best for her," Community Services Manager Linda Cochrane said. "It's been challenging in that regard, it's been challenging for our staff that are very committed to the welfare of Lucy,

"It does give us some peace of mind that we are doing the right things for her."

Zoo officials said recently her health has been improving – she has lost more than 450 kg (about 1,000 lbs) after being put on a weight loss program.

A spokesperson for Voice for Animals told CTV News they had been hopeful the Supreme Court would hear their case after the two-to-one decision by the provincial appeal court.

One of the Appeal Court justices wrote a dissenting opinion, saying the groups should have public standing in the matter and it should go to trial.

Regardless of this most recent decision, Reece said the animal activists will keep fighting to have Lucy moved.

"The one thing for sure, is that we're not going to give up."

With files from Susan Amerongen