They are one of the oldest mammals, belonging to the same group as the platypus, however, the long-beaked echidna — native only to New Guinea — is one of the least studied animals on the planet.
They are monotremes, animals that are genetically in transition. From the NY Times:
Echidnas keep their cool, all right. “They’re one of the most pacifistic mammals,” Dr. Rismiller said. “Nobody bothers them; they don’t bother anybody. There’s a lot we could learn from them.” And in that level head sits a mighty brain. Among humans, the neocortex that allows us to reason and remember accounts for 30 percent of the brain; in echidnas, that figure is 50 percent.
If only they could stand to teach us. Short-beaked echidnas put up with people, however grudgingly, but as Mr. Opiang learned, the long-beaks of New Guinea shun all signs of human habitation, perhaps because, being twice the size of short-beaked echidnas, they are prized as bushmeat by local hunters and their dogs. “They’re not attracted to baits,” he said. “You can’t catch them with traps for tagging.”
To reach them, you must hike for miles into the highlands, on treacherously steep and slippery terrain where it rains 275 inches a year. “It’s one of the wettest places on earth,” Dr. Wright said.
Most importantly, the male long-beaked echidna packs a four-headed penis. Also, they sorta look like a photoshopped combination between a porcupine, crane, mole, pig, turtle, anteater. Not too shabby.