The Greater Vancouver Zoo says it is now home to three grizzly bear cubs from Alberta that would have otherwise been euthanized.

A photo captured over the weekend by a Calgary family has experts excited about what could be the first spotting ever of a grizzly with a white head but regular brown colouring on its body. 

The bear, which has been nicknamed Nakota by locals, was first revealed publicly after it was spotted in Alberta's Banff National Park in late April.

The letter -- signed by 73 scientists, educators and conservationists from Alberta, British Columbia and outside Canada -- says Alberta is ignoring its grizzly population.

A sign attached to grizzly bear enclosure enclosure warns visitors of the broken glass.

From the tip of the sow's nose to her tail, she is 20 feet long; from her feet to the cubs that will be attached to her back, she will tower 17 feet tall.

Witnesses told officers the bear was shot in the spine and could only move by dragging itself with its paws.

COS officers said none of the bear's parts that might be popular with poachers, such as its paws or head, had been taken.

The bear backed away, and the pair spent several moments in an uneasy standoff, in which the man said he couldn't tell who was bleeding to death faster.

The incident happened Monday in the backcountry about two hours north of Powell River on the Sunshine Coast.