What do we mean by “intelligence?” I’ve known any number of people in my life who struggled in school, couldn’t read, and were worse spellers than I am. And yet, they could fix an old tractor out in the field with just a pair of pliers and a screwdriver while I struggle to fix the carburetor on my mower, even with the help of a YouTube video. So, who’s the intelligent one?

We know humans are intelligent, but how smart are non-humans? I guess we could start by looking at brain size. As you would guess, whales have the biggest brains…sperm whales to be exact. On land, elephants have the largest brains. Both are smart, but maybe there is a better way to measure intelligence than just brain size alone. Maybe instead of size, we should look at the ratio of the size of the brain to the size of the animal. In that case, the animal with the largest brain-to-body ratio is an ant! Are ants intelligent?

There should be a better way? There is; it is called the E.Q. (encephalization quotient), which looks at how big the brain is compared to how big a brain an average animal that size is expected to have. The animals with the highest E.Q. are… #1 humans, #2 dolphins, and #3 chimpanzees. The human brain is 7.4 times larger than expected in an animal our size. The dolphin’s brain is 5 times larger, and the chimp’s is 2.5 times larger.

Are you aware that there are about 20 different species of jumping spiders in Nebraska? Is that an abrupt change from talking about intelligence? No.

Jumping spiders are the most intelligent spiders in the world, and one of the most intelligent of those is the bold jumping spider, which lives right here in central Nebraska. These spiders have tremendous eyesight, they go through elaborate mating dances, and as their name suggests, they can jump…up to 40 times their body length. For a human, that would be longer than a football field!

They don’t build webs but ambush their prey by leaping and catching them. Jumping spiders, like all spiders, have eight eyes; four are front-facing, with the middle, larger two providing high-resolution color vision, and they are telescopic. They don’t adjust a lens to focus on things at different distances like our eyes; instead, the retina moves. On either side of the larger eyes are lateral eyes that function in distance perception, and the tracking of objects. The other four eyes detect motion all around the spider.

But how smart are they? What is their E.Q.? It is small compared to humans, only about 0.4. But then most invertebrates don’t have high E.Q.’s. In a previous column, I wrote about Marcellus, the giant Pacific Octopus from the movie “Remarkably Bright Creatures,” and about how intelligent octopi are. Octopi have an E.Q. that is the same as that of the bold jumping spider!

Maybe we can’t interact with octopi here in central Nebraska, but we can interact with something every bit as intelligent! The bold jumping spider! The following link will take you to a guide to identifying Nebraska spiders: https://extensionpubs.unl.edu/publication/ ec1590/2016/pdf/view/ec1590-2016.pdf