Damselfish can recognize members of their own species by their unique facial patterns, detectable to us only under ultraviolet light. The fish were tested under conditions where they were rewarded for swimming toward an image of a fish-face they had seen before over a novel image. They overwhelmingly picked familiar faces. Since fish swim in groups, it may benefit them to know their neighbors.
Also, the title of the article should be "Not just a human skill!" - as it is surprisingly not a human skill...
Which blue circle looks bigger? They're the same size. This illusion is called the "Ebbinghaus illusion" and it turns out, even fish are susceptible to this visual trickery. Some fish were trained to prefer large circles, and some to prefer small circles. Their test choice depended on the appearance of the circle in relation to a group of differently-colored, differently-sized circles.
Assassin bugs, as you might guess from their name, kill other bugs. But some species take it to the next level, sucking the corpses of their victims dry, and wearing them - often MANY of them! These corpses function as both visual and olfactory camouflage, and may offer some physical protection as well. Fascinating! Read more here.
I've had plenty of urban encounters with raccoons and they kind of scare the crap out of me. Like many urban "pest" species, they are amazingly understudied given their obvious problem solving behaviors and survival skills. Jason Goldman tells us more about the behavior and lifestyle of this fascinating animal.
Spiders in both the Phillippines and Peru have been observed building decoy spiders. This behavior had never been observed before but brings up so many questions! Are there evolutionary advantages? Are some decoy spiders better than others (depending on why they do this in the first place!) Is this tool use in a spider? Can they count to eight? I see a field of research developing before our eyes!! Read more here