Picture a hunter stalking its prey.

Its keen eyes constantly take in its surroundings  and plot the best course to its unwitting lunch. It plans its attack based on the victim’s  attributes and immediate surroundings,   and uses these to pin its victim down.

It patiently executes every move with not  merely primal instinct, but wily calculation. It's done this before and has  honed its approach with experience. At just the right moment, it pounces  with a big leap, taking down its meal.

This sounds like a scene from Tom and  Jerry, or like a human hunter in the woods. But what I’m describing is not a cat, or  even a mammal, or a bird or a reptile. It’s not even a vertebrate.

It’s a spider. And not just any spider, but a genus  of jumping spider known as Portia. These spiders are so smart that they have  upended how scientists look at cognition,   especially in invertebrates.

They’re forcing us to totally  rethink how we think about thinking. [♪ INTRO] So these spiders are among  certain invertebrate species,   including octopuses and bees,  changing how we see cognition Before researchers started taking a closer look  at these animals, they assumed that an animal’s   cognitive abilities should be roughly proportional  to morphological complexity and brain size. Researchers believed that something with  an exoskeleton and a brain smaller than   a pinhead shouldn’t be capable of the  things Portia can very obviously do. We’re talking about things like  learning through trial and error,   anticipating future events, intentional deception,   and even REM-like sleep behavior, complete  with eye movements and twitching limbs.

The processing power required  to run the animal’s cognition   should not fit into such itty-bitty hardware. And yet, the spiders think in uncanny ways,  like learning through trial and error. Think of a cat failing to  snag a mouse that escaped   under a gap in the door just in the nick of time.

It’s really hard to fool Simba twice. Let’s look at how their expectation-defying antics  have researchers calling Portia eight-legged cats. First, a quick primer on cognition.

The term broadly covers all  forms of thinking and knowing. By contrast, something that’s a  result of sheer instinct or reflex   is not generally considered a cognitive process. In rating cognition, we traditionally place   primates at the top, followed by  mammals, then other vertebrates.

Although more recently, the intelligence  of certain non-mammalian vertebrates,   like crows and ravens, has thrown  a wrench into this ranking. All in all, though, invertebrates  have come in last place. Increasingly, though, cognition research looking   at animals has been criticized for judging  intelligence against human ways of thinking.

Super-smart invertebrates like Portia  are helping challenge this view. Salticids are a family of thousands  of species of jumping spiders. And some of them display feats that invertebrates  were thought to be simply incapable of.

Portia species are among  the most studied salticids,   and scientists have learned that, in a  nutshell, they are unbelievably smart. Unlike many spiders, they prefer  to not build webs to catch prey. Their meal of choice is other  spiders, so that kinda makes sense.

Instead, Portia see prey from a distance,   consider the situation carefully, and  then execute their little spidey plan. Until the late 20th century, scientists  thought that these spiders’ behaviors   were entirely hardwired,  not conceptual or learned. In the 1980s, researchers began  to study their uncanny abilities.

And we are going to get to what they learned,  but first we’re going to take a quick break. Thanks for watching this SciShow video! And thanks to everyone for supporting SciShow, even over the holidays.

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Every detail shows the care, creativity, and humanity that goes into making things that are worth making, and by purchasing one you are directly supporting Complexly getting to make more stuff. We couldn’t do all of this without you. Spiders are known for their eight eyes.

But Portia species have two large,  distinctive, dare we say even cute   primary eyes on the front of their faces,  giving them a sort of cat-like look. Their other six eyes are much smaller,   arranged in three pairs behind the primary  set, each serving its own secondary function. Their unique arrangement of eyes  gives them an amazingly detailed,   wide, and far out field of vision  compared to even other spiders.

But eyes only see. What’s exceptional about these spiders  is not just their visual perception,   but how they think about what they see. Like planning based on representation, which  was once thought to be exclusive to vertebrates.

In this context, representation isn’t like repping  your favorite sports team or band with a t-shirt. It’s the ability to recall and consider  a mental symbol for an abstract concept   or a thing, even something that isn’t  perceivable in the immediate environment. These spiders have a thought process akin to what   might happen when you see  a food truck blocks away.

Roughly, you would bring up  the concept of a food truck   and the concept of making a purchase,  decide you’re going to go do that,   plan a path to get to the truck, pull out  your wallet, order, and scarf down a taco. But the whole process is  far more detailed than that. It’s not an automatic see taco,  put taco in belly situation.

Likewise, these spiders see food  from far away, think about it,   and then plan to attack and chow down. For example, a 1997 study looked  specifically at at Portia fimbriata,   an Australian species known for its especially  long and complicated detours while hunting. Experimenters placed spiders on a platform  in a spot where their food was visible,   but with no direct linear route to get to it.

They were able to chill for a moment  while visually scanning the area. Then they were able to choose and take  the necessary detour around obstacles,   even when they had to lose  sight of the lure on their path. Subsequent experiments using more complicated  setups suggest they'll persist on a detour for   as long as an hour, or even more,  after losing sight of the target.

So they have a form of object permanence,  which is also unexpected in invertebrates. They can also assess risk. Some Portia species like to eat spitting spiders.

But, guess what spitting spiders do. Their sticky weapon can gum Portia down, allowing  the prey time to attack the immobilized predator. So Portia needs to stay out of the line of fire.

Studies show that, when they see one of these  spitting critters in its web, they think to   themselves that this thing can saliva-bomb me from  the front, so I will have to get around the back. But when it sees a spitting spider  carrying an egg sac, it thinks, “Ah, this one is not going to spit because its  mouth is full, so I can pounce straight on.” If that wasn’t remarkable enough,   they also seem to be able to deceive prey  spiders by pretending to be harmless. Web-building spiders sense whether a  prey insect or predator has invaded   their web by feeling the vibration  patterns through the strands.

Well, Portia spiders have a trick for that, too. They have practically endless combinations   of abdominal and limb movements that  can mimic these vibrational signals. They throw these signals out one by one  in rapid succession until they hit on   the pattern of something their prey  favors, like a mate or insect prey.

The prey spider is naturally intrigued by  what they believe is a potential sexual   partner or their next serving of protein,  and sends favorable vibrations in return. Portia recognizes the meaning of  other spiders' vibration patterns,   and doesn’t make its move until  its prey seems thoroughly deceived. They’re using trial-and-error to get and keep  their prey’s guard down until it’s too late.

All of these antics make Portia a useful  model for re-evaluating and testing our   hypotheses about cognition and  how it arises across species. Their abilities demonstrate the flaws in  the view that human intelligence is the   only benchmark by which to evaluate other species. The traditional anthropocentric, or human-centered  view is that abilities like language, planning,   and holding abstract concepts  in our heads evolved together,   clustering in humans as the pinnacle of cognition.

The updated biocentric view assigns equal  intrinsic value to all life forms and habitats,   and sees each cognitive ability as  being selected for by the environment. Portia spiders live in various  diverse habitats on the African,   Asian, and Australian continents,  so the idea is that their cognitive   prowess would have evolved to suit  each of their own unique circumstances. This suggests that, to some extent,  myriad cognitive abilities may   have evolved in varied combinations  depending on species’ varied needs.

Rather than seeing language as  a superior cognitive ability,   for instance, the idea is that some species  just don’t need language as we know it. In other words, something like trial-and-error   web vibrations may seem primitive compared  to language, but maybe it’s just different. So there you have it.

Scientists have a lot more to learn about  these spiders’ uncanny cognitive skills. And maybe when we learn those things we will   admit that Portia spiders are  intelligent in their own right. Not just smart “for spiders,”  but just plain smart. [♪ OUTRO]