Aurora, the 20-year-old beluga whale who gave birth to a calf Sunday, is bonding well with her newborn baby, according to marine mammal staff at the Vancouver Aquarium.

The still-unnamed 70-kilogram calf was born at 3:39 p.m Sunday, after three hours of labour.

Caregivers and veterinarian teams monitored mom and baby heavily overnight, and say the pair is showing positive behaviours and strong interactions. The calf is continuing to swim alongside her mother, and nursing is underway.

In Pictures: Beluga gives birth at Vancouver Aquarium

"Aurora and her calf are coming along nicely together. There are several critical milestones for the calf to reach over the next few days and weeks," Dr. Martin Haulena said.

"Aurora is doing a great job and we continue to see her maternal instincts come to the fore."

The calf and mother will remain under 24-hour observation for several days to monitor their progress.

Aurora's other daughter Qila and her one-year-old calf Tiqa were returned to the tank Monday morning, and are getting along well.

In preparation for Sunday's birth, the whales were temporarily removed to allow the maximum space for her birth and avoid interference from the other animals.

This is the first time in the facility's history two beluga calves will share a habitat.

Haulena says the two mothers and daughters swam in pairs at first, and then Tiqa "became increasingly curious about the new baby," following Aurora and the calf around the pool.

The newborn will remain unnamed until the fall, when it is expected members of the public will be invited to submit suggestions.

A smooth delivery

Sunday's delivery of the 1.5 metre calf was smooth, according to Aquarium Vice-President Clint Wright.

"Aurora went through the birthing process very, very well," Wright said.

"She was very calm throughout; she certainly didn't look to be in any severe pain or discomfort."

Haulena says they are very confident about Aurora's mothering.

"Aurora has proven herself to be an excellent mother and grandmother and she has a very experienced veterinary and marine mammal care team standing by and ready to assist if required," he said.

Beluga whales normally gestate for approximately 14 to 16 months. On average, they give birth every three years. Newborn belugas normally weight between 116 to 154 pounds (53 to 73 kg), and can be up to 1.5 metres in length.

A precarious time

News that Aurora is bonding with her calf is welcome news to the staff at the Vancouver Aquarium.

In the hours after Qila gave birth to calf Tiqa in June 2008, the mother showed little interest in her newborn, causing concern to marine mammal caregivers because of the importance of the first breastfeeding.

"That first feed is really important because it provides all the antibodies the baby needs, really kick starts the immune system so it's really critical she gets that,'' Wright said.

Things improved after Qila's mother Aurora was brought into the tank to show her daughter what to do.

Soon after Aurora's intervention, mother and daughter could be seen swimming together in perfect unison, with mom doing most of the work and baby gliding along in the slipstream.

A whale of a time

The Vancouver Aquarium obtained its first whale, Kavna, in 1976, seven years after the animal was captured in the Hudson Bay off Churchill, Manitoba.

Imaq was taken from the same area in the late 1980s, as was another male beluga, Nanuq, who has since been transferred from the facility to Sea World in San Antonio.

The aquarium abandoned its direct-capture policy after it acquired Aurora, and now only accepts whales and dolphins that have been injured or born in captivity.

Beluga whales can reach lengths of 5.5 metres and weigh between 700 to 1,600 kilograms for an adult male. This is larger than all but the largest dolphins, but is small compared to other toothed whales.