Who knew that echidnas were so interesting?

The NYT has a nice article by Natalie Angier on the long-beaked echidna, Zaglossus bartoni.

You may be forgiven for considering one of the three remaining groups of egg-laying mammals as "primitive", yet they're anything but.

• They lay eggs but feed the babies ("puggles") with an iron-enriched pinkish milk that emerges from chest glands rather than teats.
• They have multiple sex chromosomes, not just the X and Y chromosomes found in placental mammals.
• They have a bird/reptile-like cloaca through which excretion, sex and egg-laying is performed...
• ...and male echidnas extrude their four-headed penis through this cloacal opening.
• They have long lifespans of up to 45 years in the wild.
  

Sadly these fascinating and poorly-understood animals are endangered.

More long-beaked echidna information can be found at animalinfo.org. (I'm note sure why the Latin name of the species seems to be different on the Animal Info website.)