Females in this species increase their scent markings as well as become more vocal when sexually receptive. A study between sexually active and sexually inactive pandas suggested that scent markings relate to sexual activity and captive inhabitance could be the cause for the poor reproductive ability. Males may also compete for access to a female (Liu et al., 1998; Ward and Kynaston, 1995).
Mating occurs from March to May. The female is in estrous for roughly 1-3 days. There is usually a delay of implantation which can last 1.5 months to 4 months. This may be due to climatic conditions so that the young is born at a fairly stable time. Females are less active as estrous begins, however they become restless, lose their appetite, and their vulva swells. Most of the young are born in August and September. Actual embryonic development lasts about 1.5 months. At birth, giant pandas, like all other bears are blind and helpless; but unlike most bears at birth, giant panda cubs are covered with a thin layer of fur. Newborn cubs weigh 85 to 140 grams. Immediately after birth the mother helps place the infant bear into a position to suckle. Suckling takes place up to 14 times a day and lasts for periods of up to 30 minutes. Infant pandas open their eyes at 3 weeks and cannot move around on their own until 3-4 months and are weaned at about 46 weeks. A cub may remain with its mother up to 18 months (Massicot, 2001; Helin et al., 1999; Ward and Kynaston, 1995). Breeding these bears in captivity has been an incredible challenge. Giant pandas are notorious for their reluctance to breed in captivity (Helin et al., 1999; Milius, 2001; Ward and Kynaston, 1995).
Breeding interval: Female giant pandas may breed every 2 years or less frequently.
Breeding season: Breeding is from March to May.
Range number of offspring: 1 to 3.
Average number of offspring: 1.7.
Range gestation period: 112 to 163 days.
Average weaning age: 46 weeks.
Range age at sexual or reproductive maturity (female): 5.5 to 6 years.
Range age at sexual or reproductive maturity (male): 5.5 to 6 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous ; delayed implantation
Average birth mass: 110 g.
Average number of offspring: 1.5.
It has been found from studying giant pandas in captivity that they have twins more often than previously thought--roughly half the time. The mother usually selects one and the other dies shortly after (Milius, 2001).
Parental Investment: altricial ; female parental care