Trials are under way to test whether artificial fur can be used to replace bearskin fur on ceremonial caps worn by Britain's Foot Guard regiments.
Animal campaigners oppose the use of bearskin fur
The use of bearskin fur, which has been worn for nearly two centuries, has angered animal rights campaigners.
A Ministry of Defence spokesman said it is "too soon to draw firm conclusions about the outcome of the trial".
The Guards have been accused of being party to the culling of thousands of bears in Canada each year.
Animal welfare groups estimate that around 40,000 black bears are killed every year, which they say is far more than is needed to control their numbers.
Andrew Butler, campaign co-ordinator for the People for the Ethical Treatment of Animals (Peta), told the Times newspaper: "It is outrageous that bears continue to be killed in Canada for a ceremonial hat in Britain."
However, the Household Division has stressed that none of the bears culled have been killed because of an order for bearskins from the Army.
And the MoD told the Times: "Bears are not shot for their fur. Bearskin is used from animals shot by Canadian Rangers or licensed hunters."
The Household Division says previous trials on artificial fur, made from such materials as nylon, have proved to be unsuccessful as it either soaked up water or became discoloured.
But, outlining the reasons behind the latest trial, the MoD said it "does appreciate how strongly some people feel about this issue and remains keen to reduce the requirements for new caps where possible".
A Peta campaigner is planning to demonstrate against the Queen during her official visit to Canada on 17 May by dressing as a bear and following her during her engagements.
The ceremonial headdress is thought to have been adopted from Napoleon's Imperial Guard after the Duke of Wellington's troops took the bearskin from defeated French soldiers at the battle of Waterloo.