Pygmy Hippo (Photo by Jessie Cohen)
While I write this letter, spring, with all its colors and song, is blooming just beyond my window. As the director of the National Zoo, I anticipate this season with much hope and optimism. It's a time for births at the Zoo, a busy and exciting period of new beginnings and expectations. Soon there will be young animals taking their first, steps on untried legs. Infant animals, with their chubby, rounded features and dependence on their mothers, strike something very deep within us. Who can resist reverting to baby talk and cooing away to a new-born lion or bear cub? Not long ago, on 19 April, our female pygmy hippo, Epsilon, gave birth to an infant, who, if our curator can be considered impartial enough to be believed, is "cute as the dickens . . . like a little eggplant with legs."
The forerunners of modern hippos evolved in Africa during the late Miocene about 10 million years ago and eventually reached as far as Europe and Asia about two million years ago. Over time as the climate changed and forests gave way to grasslands, early hippos probably left the wooded areas and moved to thickets along rivers, where they could feed in rivers and streams during the days and graze on the grasslands at night. In time, there was an increase in the animals' size and the modern hippo gradually emerged. Interestingly, today's pygmy hippo probably more closely resembles the ancestral hippo than does the larger, more familiar Nile hippo.
These two modern hippopotamuses are good illustrations of closely related animals that have evolved to fill different niches. Pygmy hippos are solitary and live in the dense undergrowth of tropical forests while Nile hippos live in social groups, by day submerged in the water of lakes and rivers and by night, feeding on the savanna. Their eyes, located on the tops of their heads, allow them to submerge virtually their entire body yet still watch the surrounding area. The somewhat less aquatic pygmy hippo's smaller eyes, are located on the side, rather than on top of its head. The diets also differ: the bigger hippos subsist almost entirely on grasses while the pygmies munch their way through a variety of water plants, leaves, fruits, grasses, and herbs.
Although the larger hippopotamus has been known outside of Africa since ancient times, the pygmy hippo remained a legend brought back by 19th Century European explorers of West Africa, now the countries of Liberia, Guinea, Sierra Leone, and Ivory Coast. Not until 1844 was the first pygmy hippo described by a scientist-and that was done from an incomplete skull he received from Monrovia, Liberia. Another 50 years elapsed until a live animal was seen outside Africa. Carl Hagenbeck, the legendary German zoo director, financed an expedition to Liberia which returned with five living animals. The New York Zoological Society acquired three of these animals and their arrival in the U.S. was one of the great zoo-logical events of the early 1900s. As for observations of the animal in its native range, it wasn't until the 1980s-only a decade ago-that the first scientific observations were made of the pygmy hippo in the wild.
The National Zoo had to wait until 1927 before one of these rare animals arrived. Harvey Firestone, owner of a large rubber plantation in Liberia, presented President Calvin Coolidge with a male, Billy, which soon took up residence at the National Zoo. In the next 13 years, two females were added to our collection, and by the time Billy died in 1955, he had sired 24 calves and helped to introduce many zoogoers to the charms of his elusive species. Pygmy hippos born at the National Zoo have found their way into the collection of zoos in Australia, Thailand, Sri Lanka, Singapore, Indonesia, India, South Africa, Argentina, Canada, Germany, Belgium, and England. Our most recent pygmy hippo calf, our 58th, is a direct descendant-a great granddaughter-of Billy.
Like many of the world's favorite animals, the pygmy hippopotamus is living on the edge of a precipice. Habitat destruction and a growing human population may push the pygmy hippo into the abyss of extinction and humanity could lose yet another biological treasure.