Philadelphia Zoo Announces Arrival of Critically Endangered Western Lowland Gorilla for Species Survival Plan Breeding Program

Philadelphia Zoo is thrilled to announce the arrival of 11-year-old female western lowland gorilla Patty to its growing family.

Patty came to the Zoo on an Association of Zoos and Aquariums (AZA) Species Survival Plan (SSP) breeding recommendation with the Zoo’s silverback, Motuba, to ensure the survival of this species and maintain a genetically diverse population. Western lowland gorillas are considered critically endangered by the International Union for Conservation of Nature (IUCN). Western lowland gorillas are threatened by a number of things including habitat destruction due to mining and logging.

“Patty is a wonderful addition to our western lowland gorilla troop,” says the Andrew J. Baker Curator of Primates and Small Mammals Michael Stern. “Philadelphia Zoo has a rich history of successful gorilla births, and we are hopeful to see new offspring in the future as we continue our important work protecting and advocating for this critically endangered species. Our keeper team says Patty is confident and super smart.”

Patty was born October 11, 2013 at Lincoln Park Zoo in Chicago, Illinois. In her large family troop there, she played with and helped care for younger members in the group, which shows positive signs that she’ll be a great mom in the future.

Philadelphia Zoo had two successful births of western lowland gorillas in the last ten years. On August 26, 2016, now 7 ½ -year-old female Amani was born to now 29-year-old Honi and Motuba. On June 2, 2017, now 6 ½ -year-old Ajabu was born to now 24-year-old Kira via an emergency assisted birth and has since moved to Omaha’s Henry Doorly Zoo in Nebraska.

A Critically Endangered Species

Western lowland gorillas are a critically endangered species in found in lowland tropical forests of Cameroon, Gabon, Equatorial Guinea, Congo and Central African Republic. In the wild, gorillas gather in groups of 3 to 21 members, usually composed of one dominant male and various females. Young males often form bachelor groups as they mature. The male is the dominant figure, maintaining peace within the group, determining the daily routine of the troop and being the protector. They eat mostly fruit, leaves and other plant parts.

Western lowland gorilla gestation lasts around 8 months with typically a single baby born, weighing about 5 pounds. In contrast with other primates, gorilla babies cannot hold onto their mothers right away but only after about three months.  By four months old, they can walk on all fours and by six or seven months they are climbing all over their mothers.

Philadelphia Zoo is home to 5 gorillas: male Motuba and females Honi, Kira, and Patty, and adolescent female Amani.

Below are a few interesting facts about western lowland gorillas:

• Western lowland gorillas have thick black hair and a brown patch on the top of their head. When males become mature, around 13 years, they develop a silvery color hair in their back. A gorilla’s face is black with no hair, and the heads are conically elongated, particularly in adult males.
• Typical male height is about 5-6 feet when standing erect. Females are smaller.
• The male is the dominant figure, maintaining peace within the group, determining the daily routine of the troop and being the protector. The leading male can find it necessary to attract attention by noisy displays of chest-beating, ground-beating, tearing up vegetation, and short sudden sideways rushes.  Females also display and beat their chests for various reasons.
• Gorillas gather in groups of 3 to 21 members, usually composed of one dominant male and various females, but occasionally having two silverbacks, their females and offspring.
• They are diurnal and live on the ground, but will climb trees to forage for food, rest and sleep.  Females and young seem to climb trees more often, while males usually rest and feed on the ground.
• Gorillas move through the forest on the ground, by “knuckle walking,” moving on soles of their feet and the knuckles of their hands. Some days they move less than 100 yards, whereas other days they move more than 8 miles.