If you wanted to push yourself to the outermost chalk line of human endurance, you might consider an ultramarathon, or a solo row across the Atlantic Ocean, or being nominated to the United States Supreme Court.

Or you could try studying the long-beaked echidna, one of the oldest, rarest, shyest, silliest-looking yet potentially most illuminating mammals on earth.

Muse Opiang was working as a field research officer when he became seized by a passion for the long-beaked echidna, or Zaglossus bartoni, which are found only in the tropical rain forests of New Guinea and a scattering of adjacent islands. He had seen them once or twice in captivity and in photographs  plump, terrier-size creatures abristle with so many competing notes of crane, mole, pig, turtle, tribble, Babar and boot scrubber that if they didn’t exist, nobody would think to Photoshop them. He knew that the mosaic effect was no mere sight gag: as one of just three surviving types of the group of primitive egg-laying mammals called monotremes, the long-beaked echidna is a genuine living link between reptiles and birds on one branch, and more familiar placental mammals like ourselves on the next.

Mr. Opiang also knew that, whereas members of the two other monotreme genera, the duck-billed platypus and short-beaked echidna, had been studied for years  last May, the entire genetic code of the platypus was published to great fanfare  the life of the long-beaked echidna remained obscure and unsung.