How Big Is a Baby Panda at Birth? Panda Cubs Explained

How small is a newborn panda?

A giant panda mother weighs about 70–125 kg (150–275 lb), yet her newborn cub weighs about as much as an apple. Most estimates put the newborn at somewhere between 1/800 and 1/1,000 of the mother’s weight. For comparison, a human newborn is around 1/20 of its mother’s weight.

Newborn cubs are pink, with only a thin covering of short white hair. Their eyes are closed, they have no teeth and they cannot move much on their own. They are noisy, though, and squeal loudly when they need warmth or milk.

Why are panda cubs so small?

All bears give birth to small, undeveloped cubs, and the giant panda is the most extreme case. Part of the reason is the way panda pregnancy works. After mating in spring, the fertilized egg floats freely in the womb for weeks to months before it implants, a process called delayed implantation. The total pregnancy lasts about 95–160 days, but the embryo grows only during the last month or two.

Scientists are still debating why bears evolved this pattern. One idea is that a short pregnancy with a long period of nursing suits mothers that cannot afford to feed a big fetus for months. For a panda living on low-energy bamboo, putting energy into milk after birth rather than into a long pregnancy may be the more efficient strategy. Studies of newborn bear skeletons suggest that panda cubs are at a similar stage of development to other bear cubs, just smaller.

Twins and the mother’s choice

About half of giant panda births produce twins, and triplets are very rare. In the wild, a mother usually raises only one cub. She cannot carry, nurse and keep two helpless cubs warm while also leaving the den to feed, and the second cub usually dies.

At breeding centers in China and in zoos, keepers often “twin swap”: they keep one cub in an incubator while the other is with the mother, then switch them every few hours. This lets both twins nurse and be groomed by the mother, and many captive twins now survive.

How baby pandas grow

Panda cubs grow quickly once they start nursing. Typical milestones are:

• 1–3 weeks: the skin darkens where the black fur will grow.
• About 1 month: the black-and-white pattern is complete.
• 6–8 weeks: the eyes open.
• About 3 months: the cub starts to crawl.
• About 5 months: it walks steadily and begins exploring near the mother.
• About 6 months: it starts nibbling bamboo, although milk remains its main food for much of the first year.
• About 1 year: it can weigh around 45 kg (100 lb).
• 18 months to 2 years: it leaves its mother and lives on its own.

For the first weeks, the mother holds the cub almost constantly against her chest, cradling it in one paw. She may not leave the den to eat or drink for several days after the birth. As the cub grows, she leaves it in the den or in a tree for longer periods while she feeds.

When are panda cubs born?

Giant pandas mate in spring, usually between March and May, and most cubs are born from August to early September. Wild mothers give birth in a hollow tree or a rock cave. Females usually have their first cub at four to eight years old and then breed about every two years, so a wild female raises only a small number of cubs in her lifetime. This slow pace is one reason panda numbers recover slowly; see are giant pandas still endangered?

How do panda cubs compare with other bear cubs?

All young bears are called cubs, and all are born small, blind and helpless in a den. Black bear and brown bear cubs are born in midwinter while the mother hibernates, while panda cubs are born in late summer because pandas do not hibernate. For more about bear cubs in general, see what is a baby bear called?

Myths and facts about baby pandas

• Myth: panda cubs are born premature. Fact: they are born at the normal end of the pregnancy; they are simply very small, like other bear cubs.
• Myth: mothers abandon one twin because they do not care for it. Fact: in the wild a mother cannot physically care for two newborns at once, so she concentrates on one.
• Myth: baby pandas are born black and white. Fact: they are pink at birth and develop their pattern over the first month.