Mating season only occurs once a year, between February 15th and March 30th, period during which the female panda is only fertile for 48h.
When our female is in heat, we bring the panda pair together, while they live the rest of the time in a solitary way, like in their natural habitat.
If the pandas do not mate naturally, an artificial insemination can be made. It is part of a research program for the species conservation, since it is threatened in the wild.
If the fertilization succeeds, the embryonic diapause starts. But what is it?
Diapause is an almost systematic phenomenon for all bears. The oocyte is not nested and therefore there is no hormonal impregnation. Embryonic development is then stopped.
The end of the diapause happens by behavioural changes (exhaustion and lose of appetite) and hormonal changes (hormonal increase observable by daily urine samples and weekly analyses) that show the beginning of the pregnancy or pseudopregnancy.
Female pandas can indeed experience pseudopregnancy: during this period, of a duration of 3 to 6 weeks, they are not actually pregnant but they exhibit the same behaviours as pregnant. At this stage, it is impossible to know whether the female is pregnant or not.
To have a confirmation of the gestation, the only way is to check visually with an ultrasound scan the presence of an embryo. This one is only detectable 3 weeks before birth. Sometimes, the cub is so small that it is only perceptible at the extreme end of the gestation.
24h to 48h before birth, the female panda’s progesterone level drops down. It decreases slower if the female does not give birth, which shows she was experiencing a pseudopregnancy.
If the female is really pregnant, 24h after this hormonal fall she gives birth to a 150 grams (5 ounces) cub. A litter can also be made up of 2 to 3 cubs!
The female panda and her cub are then sheltered in their inside area. The visitors will be able to see them about 3 months after birth.