Panda Mating Season Is Approaching
/ Post by Pandas International
Pandas are unique in their mating cycles among all bears. While the mating season for the Giant Panda is quite long, from January to June in some areas, each female panda will only be in her reproductive (oestrus) cycle once during those months. Furthermore, during the cycle, there is only a small window of time (1 to 3 days) when successful fertilization can actually take place leading to the low reproductive rate in the species.
Giant Pandas exhibit another peculiar evolutionary adaptation known as delayed implantation. A fertilized giant panda egg does not immediately implant on the mother’s uterine wall, but instead “floats” around in her reproductive tract for varying lengths of time. As a result, we do not know precisely the length of the giant panda’s actual gestation period. All we can say is that the time from mating to birth ranges from 95 to 160 days.
Delayed implantation gives the giant panda more control over when cubs are born because birth dates are not precisely fixed by mating dates. Young may be born in the late summer or in the fall. Overall, however, the general timing of giant panda reproduction is determined by the importance of weaning cubs in the spring, when the newest most protein-filled bamboo shoots are available. This gives cubs the best possible start in life on a diet that is of a higher nutritional quality.
Females give birth to one or two cubs. Triplets are extremely rare. If twins are born, usually only one survives in the wild. The mother will select the stronger of the cubs and the weaker will die. It is thought that the mother cannot produce enough milk for two cubs since she does not store fat.
Cubs will stay with their mothers for about two years. Therefore females only reproduce every other year or less, adding again to low reproductive numbers.
Many zoos have tried to breed Giant Pandas but with limited success. The breeding centers in China use both natural mating and artificial insemination and have become much more successful in the past few years. Nevertheless, the wild Giant Panda population is steadily declining, and recent successes with captive breeding have not made up for the losses, either in the wild or in zoos.
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