The platypus is Earth's weirdest creature - famously, 19th century biologists thought it was a hoax when first shown one - and its venom is a hodgepodge too, containing toxins borrowed from snakes, spiders, and even starfish.
The fact that the platypus has venom at all is incredibly unusual for mammals, but then there's very little that's "normal" about the creature. One of the very few monotremes in the world, the platypus lays eggs and has no nipples, but they have hair and the female still produces milk, making it more mammal that not. The creatures are thought to create their venom to show dominance during mating season, and the males shoot the poison from little barbs in their feet.
Researchers have now found that the toxins in the poison are an amazing example of convergent evolution, in which separate evolutionary paths come up with very similar solutions to the same problems. Some examples of convergent evolution are incredibly basic, like the fact that vastly different species have all come up with the same basic structures for eyes and wings.
But here, the platypus has come up with dozens of nearly identical toxin proteins to those found in other animals. Only about three of the toxins are unique to the platypus - the rest are almost identical to ones found in such wildly disparate creatures as starfish, sea anemones, spiders, snakes, and lizards. The 83 different toxin genes fall into at least 13 distinct families, different combinations of which can cause inflammation, nerve damage, muscle contraction and blood coagulation...not to mention excrutiating pain.
For more on what platypus venom can do to you - including possible new life-saving drugs - check out Nature News.