sorry booty Black widows have surprisingly good memories

Black widows must despise Clint Sergi. While working on his Ph.D. In biology at the University of Wisconsin-Milwaukee, Sergi spent his time designing little challenges for spiders — which often consisted of rewarding them with delicious dead crickets or confusing them by stealing the crickets. “The big question that motivated the work was just knowing what goes on in the minds of animals,” he says.

Biologists already know that spider brains aren’t like human brains. Your sensory world is geared towards life in webs and dark corners. “Humans are very visual animals,” says Sergi. “These web-building spiders have almost no vision. They have eyes, but they’re particularly good at sensing light and movement.” Instead, he says, a black widow’s perception relies mostly on vibration, much like hearing. “Their legs are like ears that pick up the vibrations through the mesh.”

And when it comes to cognition, biologists know that these spiders remember when they’ve caught prey. Some scientists, including Sergi, believe they even form mental representations of their webs. However, not much is known about how detailed her memories are or how past events affect her future decisions. So Sergi and his advisor, spider-recognition expert Rafa Rodríguez, decided to test the Black Widow’s memory. As you can imagine, Sergi offered dead crickets to spiders and then stole them back.

The result, they write in the journal Ethology, shows that black widows have better memories than previously thought. Once their prey has been spirited away, the spiders keep looking for it in the right place. In some cases, they seem to remember the size of the prey – they’re looking more for the biggest stolen snacks. “They don’t just react to a certain stimulus with fixed behavioral patterns,” says Sergi. “You have the ability to make decisions.”

This work is a reminder that complex cognitive computations are widespread in the animal kingdom—that internal navigation systems appear in both large and tiny brains, including those that depend on vastly different sensory inputs. “It shows that arthropods are able to encode complex memories that humans often associate with vertebrates,” says Andrew Gordus, a behavioral neuroscientist at Johns Hopkins University who was not involved in the work. “Invertebrates are far more sophisticated than we give them credit for.”

Sergi’s findings add to the growing body of evidence that insects and spiders form — and respond to — detailed memories similar to how humans do, but with vastly different machines. We orientate ourselves on “place cells” in the hippocampus, which arthropods lack. Still, says Gordus, “they have brain regions that have evolved to perform the same function.”

Your central nervous system contains a spinal cord and a 3-pound brain. Spiders have two sets of neurons called ganglia: one above the esophagus, one below. The critical input to this brain comes from thousands of sensors along the spider’s exoskeleton called slit sensilla. Each looks like a tiny crack that deforms as vibrations sweep through the spider’s body. (Some evidence suggests widows can tune into different frequencies by adjusting their posture.) Spiders are so well wired to sense vibrations that even whether the spider web is part of their brain has been debated.

Compared to humanity’s vast lump of gray matter, this appears to be a radically different memory-processing computer. But for Sergi, what an animal’s brain looks like is less important than the behaviors it produces. For example, as a biological class, birds share a common brain structure. However, some excel at cognitive tasks that others cannot. Crows count and use zero. Cockatoos solve logic puzzles. Blue jays hide food in the summer and fall, then remember where to find them in the winter. Even among mammals, another class with similarities in brain structure, some animals are better than others at finding hidden food. Squirrels, of course, are great at it. “They have a normal mammalian brain, but they’re much better at remembering where they’ve put things than humans,” says Sergi. “But you wouldn’t necessarily see that just by looking at the anatomy of the brain or by watching what they’re doing on an MRI.”