National Geographic : 1949 Feb
Biggest Worm Farm Caters to Platypuses BY W. H. NICHOLAS IN THE CELLAR of its lion house, New York's Bronx Zoo operates the biggest earthworm-breeding farm in the world. The Zoo's pampered duck-billed platypuses, Cecil and Penelope, are the cause of this wholesale worm manufactory. They demand 25,000 big earthworms in their diet each month, along with an assortment of night crawlers. Even the untimely death, last September, of their comrade in captivity, Betty, didn't help the situation much. Winter was coming on and a worm's growth in winter is slow. To supply the main dish on the menu for two platypuses in cold weather is as much of a job as doing it for three in the summer. When Cecil, Betty, and Penelope embarked on the high seas, en route from their Austral ian homeland to New York, in the spring of 1947, Zoo authorities began to worry about supplying them with worms. To Christopher W. Coates, curator of the New York Aqua rium, went the dubious honor of assuring the platypuses a regular daily handout. Food Worms Short-and High-priced "I wrote to commercial earthworm farms, of which there are about 10 or 15 big ones in the country," Mr. Coates told me, "asking them for prices and quantities. I soon received a rude surprise. I discovered, first, that costs were prohibitive, and, second, that the com mercial worm farms in the country couldn't supply enough earthworms to meet the needs of our platypuses. "So we had to start from scratch and build up our own supply from what breeding stock we could purchase. "The platypuses need two pounds of worms a day. Depending on size, from 150 to 1,000 worms weigh one pound. Of the large size we generally supply, the platypuses consume 25,000 worms a month. "Our initial order for worms was for 25,000. After three months had elapsed, the dealer finally shipped us 3,596. They arrived about 4 p.m. on Friday, December 20, in the middle of a snowstorm. Christmas fell on the follow ing Wednesday, and I had made plans to go away from the Zoo for a long week end. My trip had to be abandoned, for the worms demanded immediate care. "No one at the Zoo, including myself, knew much about worms. I distinctly recall picking them up gingerly, one by one, with a pair of tweezers. I soon got over that, and so did tankmen Thomas Callahan and James Malcolm, two Aquarium attendants who were assigned to the actual work of handling the worms. Worms Flown to Panama "We felt our way along, and by early April, 1947, we had built up a stock which encour aged us. Then we received a telegram from Mr. David Fleay, the Australian naturalist who was bringing the platypuses to America, advising that he had run out of worms in mid Pacific and requesting that we fly a consign ment of 10,000 to Panama to meet his ship when it passed through the Canal. This we did, although we felt sorry about depleting our breeding stock at this point. "Then came another blow. The platypuses rejected some of the worms. That meant we had to grow better ones. We went all over Bronx Park looking for various types of worms. By the time the platypuses arrived in late April, 1947, we had found an unidentified species that turned out to be satisfactory. We called them 'fighter worms' because they are so active, although now we refer to them as 'leafworms,' because they occur in decayed leaves. We haven't had time yet to identify our worms scientifically. "We discovered that our stock thrived best on a basic mixture of soil and elm leaves (page 272). We also discovered that night crawlers were satisfactory as supplemental rations, although the platypuses will not eat them exclusively for more than two days at a time. "Callahan and Malcolm entered into the spirit of the thing, for this was a definite challenge to all of us. They would come back to the park after dark and spot likely places for finding worms. And they have become adept at catching night crawlers, too. "With a red lantern one man walks along the grass parallel with a strip of sidewalk, picking up the crawlers as fast as he can and tossing them on the concrete. He sometimes walks 100 feet doing this and then retraces his steps, scooping the crawlers off the side walk. The crawlers aren't bothered by the red light, and do not vanish as they do when prospective fishermen go hunting for them with a bright flashlight. "We have bred night crawlers in captivity, for the first time to my knowledge. "In the early days we used to count the worms, but, as our volume of production rose, we discarded that tedious method and now measure them out in containers which hold two pounds, or a one-day supply.