The staff at Franklin Park Zoo is pleased to announce that Cleopatra, a pygmy hippopotamus, is expecting.

If all goes well, this will be the first successful birth of a pygmy hippo at Franklin Park Zoo. The pregnancy was detected via ultrasound on Sept. 4, 2018 when Cleopatra, affectionately known as Cleo, was about four weeks pregnant. The gestation for pygmy hippos is six to seven months, and Cleo is expected to give birth in mid to late February.

“We have been regularly monitoring the pregnancy via ultrasound to learn as much as we can about normal development,” said Dr. Eric Baitchman, Zoo New England Vice President of Animal Health and Conservation. “Not much is known about the development of pygmy hippo calves in utero, but thus far the calf appears to be healthy. We have observed the calf moving on the ultrasound and have detected the heartbeat. Due to the wonderful training program between Cleo and her keepers, we are the first ones that have ever been able to monitor a pygmy hippo pregnancy via ultrasound from early gestation. Other zoos in the U.S. and Europe are typically only able to first detect a pregnancy at around three months, or nearly halfway through gestation.”

The small North American captive population of pygmy hippos consists of 103 individuals, and is skewed toward females. Zoo New England participates in the Pygmy Hippo Species Survival Plan (SSP), which is a cooperative, inter-zoo program coordinated nationally through the Association of Zoos and Aquariums (AZA). SSPs help to ensure the survival of selected species in zoos and aquariums, most of which are threatened or endangered, and enhance conservation of these species in the wild. Cleo’s pregnancy is a result of an SSP breeding recommendation with her mate Inocencio.

In a cooperative, international effort, Inocencio arrived at Franklin Park Zoo in December 2013 from the Parque Zoologico Buin Zoo in Chile where he was born. Inocencio arrived a few days before his second birthday. At the time of his arrival, he was too young to breed with Cleo. As pygmy hippos are solitary animals, the eventual introduction between Cleo and Inocencio was carefully coordinated.

“This pregnancy is the result of years of planning,” said John Linehan, Zoo New England President and CEO. “While we are thrilled that Cleo is expecting, we are cautiously optimistic and are hoping for a successful delivery of her calf. This birth will contribute to the preservation of this species.”

Pygmy hippos are native to West African rainforests in the countries of Sierra Leone, Guinea, the Ivory Coast and Liberia. This endangered species faces increasing threats including shrinking natural habitat as the result of logging, farming, mining and human settlement.

Because of their reclusive nature, they are difficult to count in the wild. According to the International Union for Conservation of Nature (IUCN), it is estimated that there are between 2,000 and 2,499 individuals left in their native habitat in West Africa.

While Cleo’s pregnancy is the result of natural breeding, prior to this Dr. Baitchman led an effort at Zoo New England to develop artificial insemination techniques for this species. After years of preparation, in 2016 Zoo New England accomplished something never before achieved by any zoo in the world: we successfully thawed viable samples of pygmy hippo semen which had been collected from Inocencio and frozen in liquid nitrogen. The milestone marked a major step forward in securing a better future for these endangered animals.

Staff monitored the daily behavior of Cleo, and collected skin secretions, saliva, and fecal samples to help determine when she was ovulating. A critically important part of this process was acclimating Cleo to the training chute for regular ultrasounds. Zoo New England’s Animal Care staff employed operant conditioning and positive reinforcement training techniques to successfully acclimate her to the space and procedure.

Prior to the introduction to Inocencio, staff did attempt to artificially inseminate Cleo which did not prove successful. Despite this, Zoo New England’s staff gained a lot of knowledge and experience that can be shared with colleagues as we work collaboratively to better understand the reproductive physiology and behaviors of these endangered animals – all of which may help to bolster the numbers of this species in the future.