MOLTO interessante — echidna e ornitorinco sono dei mammiferi ovipari appartenenti all’ordine Monotremata. Ecco dei brani tratti dall’articolo del New York Times che mi ha catturato:
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.
Another avianlike feature is the cloaca, the single orifice through which an echidna or platypus voids waste, has sex and lays eggs, and by which the group gets its name. Yet through that uni-perforation, a male echnida can extrude a four-headed penis.
“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.