On the Trail of a Monotreme

June 11, 2009

Once considered “mission impossible,” a grueling study of Papua New Guinea’s long-beaked echidna reveals this rare, egg-laying mammal’s elusive habits.

Experts have called the long-beaked echidna impossible to study, but the challenge didn’t deter Muse D. Opiang. The Wildlife Conservation Society research intern spent thousands of hours over several years on the trail of the porcupine-sized creatures in the wilds of Papua New Guinea. His grueling work in PNG’s Crater Mountain Wildlife Management Area represented the first study of this rare, egg-laying mammal.

The long-beaked echidna, also called the spiny anteater, lives only in New Guinea and belongs to the primitive order of mammals called monotremes, which also includes the platypus. These creatures’ unusual reproductive systems forced zoologists to change their very definition of what a mammal is.

WCS supported the work by Opiang, who is now with the Papua New Guinea Institute of Biological Research. His study, published in the Journal of Mammalogy, chronicles the long-beaked echidna’s foraging behaviors, movement patterns, and home-range sizes.

Pinning down the nocturnal, subterranean habits of the echidna required nearly 6,000 hours of field work over four years, beginning in 2001. In fact, Opiang spent 500 hours just tracking down the first animal. In the end, he managed to capture 22 individual echidnas (15 adults and 7 juveniles), and affixed radio transmitters to 9 adults and 3 juveniles. As the first to study the unusual species, Opiang perfected his research methods by trial and error. Initially, he attached transmitters the echidnas’ spines, but the animals shook them off in the course of their constant burrowing and digging. So Opiang switched to the ankle—which proved more reliable.

The study located over 200 den sites, mostly underground, though some echidnas made their dens in cliff faces or thick vegetation. One lactating female was found; echidna mothers rear their “puggles” in a sticky pouch for the first 40–50 days and nurse them from two mammary skin patches until they are weaned, at about seven months. Opiang recorded nose-pokes—a foraging behavior where the echidna pokes its tubular, toothless snout into the soil in search of insect larvae, worms, and other invertebrates. He also made note of digs: Like anteaters, echidnas excavate deep holes with their short legs and long claw. The researcher determined his study subjects’ home ranges as spanning about 96 acres.

Dr. Ross Sinclair, director of WCS-PNG, said Opiang’s research methods and insights into the natural history of this seldom seen mammal will help to manage and protect the long-beaked echidna. The species faces threats of hunting and habitat loss.

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