When Bright Colour Means "Back Off"
The poison dart frog of Central and South America carries enough batrachotoxin in its skin to kill a small predator. It is also electric blue, vivid orange, or lime green, depending on the species. This is aposematism: colouration that functions as an active broadcast of toxicity rather than a disguise. The signal is so reliable that predators learn to avoid it after a single encounter, or inherit the avoidance entirely. A 2016 study published in the journal Evolution found that aposematic colour patterns in poison dart frogs accelerated predator learning by a factor of four compared to cryptically coloured prey of equivalent toxicity. The colour is doing the defensive work the venom alone cannot do, venom kills after contact, but colour prevents contact entirely.
