Breeding Plan Keeps African Penguins Afloat in Baltimore


The African penguins at the Baltimore Zoo look like proper, upstanding penguins, but looks can be deceiving. What they know about sexual trickery could teach soap opera stars a thing or two.

Take, for example, the adult female who has been reduced to hanging out with the youngsters in the nursery instead of the other adults snuggled up to each other in the nesting room.

“She’s a bit of a home wrecker,” said Steven J. Sarro, curator of birds, pointing out the pretty black and white penguin taking a twirl around the kiddie pool. “We have two out there that are nesting, and she likes one of them.”

The Baltimore Zoo’s African penguins breeding program has resulted in the largest and most prolific colony of African penguins in North America. Since the zoo began breeding in 1967, almost 800 African penguins, also known as black-footed penguins and jackass penguins because they bray like donkeys, have been produced. The zoo sells many of them to other zoos and aquariums to pay for the breeding program.


The African penguin, distinguished by a black band across the upper chest, is one of 17 species, stands 18 inches tall and weighs about eight pounds.

They used to live by the millions on the coastal islands of South Africa, but now only about 140,000 exist, in large part because of oil spills and over-harvesting of fish that the penguins rely on as a food source, Sarro said.

Unless conditions change, African penguins could be extinct in the wild in 40 years, said Sarro, who traveled to South Africa last year.

He told of visiting an island where 9,000 penguins once lived.


“We saw two,” he said.

Three years ago, the American Zoo & Aquarium Assn. selected the Baltimore Zoo to establish a species survival plan for the North American population of African penguins. The goal of the program is to produce a stable, genetically diverse population that can be acquired by zoos and aquariums worldwide.

The plan’s propagation group, which Sarro leads, includes a geneticist, nutritionist and behaviorist, as well as members of other zoos who meet regularly to share information.

The black-footed penguin was first mentioned in the journals of explorer Alvero Vello in 1497. He wrote, “These are birds as big as ducks, but they cannot fly because they have no feathers on their wings. These birds . . . bray like asses.”


Black-footed penguins became known as African penguins after 1758. The species, one of several that live in temperate climates, is listed as vulnerable, but as late as 1967 penguin eggs were served as a delicacy in South African restaurants.

The zoo’s 66 African penguins live in three rooms at the end of a long, underground tunnel. One room contains 16 plastic dog crates that line the walls and are used as nesting boxes. Couples have taken up occupancy in some of the boxes.

“Normally, they are monogamous their whole lives,” Sarro said. However, there are exceptions.

‘It is like a soap opera down here, I swear,” said Sharon Overholser, the zoo’s senior keeper of birds, who keeps track of 666 African penguins in the studbook, a registry of birds at 55 zoos and aquariums. “We used to have a female that went around breaking up all the other pairs.”


Nearly 70% of the penguins in the studbook at zoos and aquariums in the United States and Canada can be traced to the Baltimore Zoo’s penguins.

Members of the propagation group select pairs that are genetically valuable for breeding and guard against inbreeding. In some cases, they will pair penguins that don’t have a natural attraction for each other because they are a good genetic match.

Because male and female penguins are virtually identical, it frequently takes blood tests to determine their sex.

African penguins take weeks, even months, before they mate while the couple gets to know each other.


“It is just like dating,” Sarro said.

The female will lay two eggs about four days apart, the second as insurance. It takes 38 days for the eggs to hatch.

In the wild, both parents would feed and care for the young, but that isn’t prudent at the zoo because it places the young at risk of being picked on by other penguins.

So the chicks are taken from their parents at three weeks and placed in age-specific boxes in the nursery next to the kiddie pool, where they will be forced to learn to swim at about two months, after their down has turned to feathers.


“They get swimming lessons. We toss them in and they learn to swim,” Sarro said. “They don’t like it right away. They come around.”

Between 12 and 16 weeks, the juveniles are introduced to the colony.

Sarro said each penguin has its own personality. One female hates squid until a day or two before she’s ready to lay eggs, and then that’s all she wants. A male named Jack has a habit of pecking at shoes and pulling at coat hems.

“I’m crazy about them,” Sarro said. “They just mess with you.”