Amid the joy surrounding the National Zoo's newest tiny panda was the sad news that a second cub was stillborn.
Giant Panda Mei Xiang gave birth to the cubs on Friday at Washington DC's National Zoo.
The first cub was born alive at 4.83 ounces and is doing well.
Keepers watched live on the 'panda cam' as the mother groomed her stillborn cub for 17 minutes after it was born.
"When she stopped grooming, it fell from Mei's body onto the floor of the den," zoo spokeswoman Pamela Baker-Masson said email statement released late Friday.
"It lay motionless and made no sound."
Zoo officials said Sunday that the cub had severe abnormalities and was missing its brain.
A necropsy on the stillborn cub was begun late Saturday and will give clues as to why the cub stopped developing and died in the womb.
The zoo has been able to examine the live cub that was born at 5:32 pm Friday and said that it was in excellent health.
— National Zoo (@NationalZoo) August 25, 2013
DNA samples have been taken to determine both the sex and paternity of the panda cub.
The zoo said the panda's daddy is either the National Zoo's Tian Tian or the San Diego Zoo's Gao Gao.
Results of the paternity test should be available in two weeks.
The live cub is 15-year-old Mei Xiang's third newborn. Her second cub, born last year, had under developed lungs and died after six days.
Her first, Tai Shan, was born in 2005 and now lives at the Panda Base in BiFengxia in Ya'an, China.
Watch Giant Panda Mei Xiang give birth to her new cub.