TORONTO

Does the Toronto Zoo have a pregnant panda?

Zoo officials released video Thursday that may show female panda Er Shun displaying "nesting" behaviour last month - just a few weeks after she was artificially inseminated.

"Toronto Zoo staff continue to monitor her daily and watch for any unusual behaviour," the zoo stated in a press release.

The two giant pandas arrived at the Toronto Zoo from China back in March 2013.

Er Shun was inseminated earlier this year after zoo staff determined the time was right. A press release from the zoo said Er Shun "was showing signs of estrus with elevated estrogen levels and decreased progesterone levels" leading up to the April 27 insemination.

Officials decided to inseminate Er Shun because Da Mao - the five-year-old male panda - "was too sexually immature and did not show any interest in breeding at this time."

If Er Shun is pregnant, zoo staff say they won't know until 20 days before she gives birth. A giant panda's gestational period is three to five months.

"Staff are currently training Er Shun for ultrasound and hope they will be able to see a fetus during this time frame," the zoo stated.