The mouth of the pacu fish — gigantic, 60-pound cousin to the more well-known (but much smaller) piranha — demands respect. Its brawny jaws and nightmarish teeth, the bottom row of which resembles a full set of exceptionally pointy human canines, are designed for crushing and tearing at seeds and nuts, its primary food …

You're looking at images of the world's two smallest frog species — Paedophryne dekot (the top two) and P. verrucosa (bottom two) — recently discovered by researchers in southeastern New Guinea.

Of all the continents, the human settlement of Oceania remains the most mysterious. We know that ancient humans walked across the now sunken continent of Sahul to reach Australia, and now some ancient trees reveal when they did it.

Jared Diamond, author of Guns, Germs, and Steel, is being sued by two Papua, New Guinea, men who claim the award-winning science writer lied about their lives to prove that tribal culture is violent.