Carbon Chemist

Tag: animal behavior

  • These Rats Learned to Drive—and They Love It

    These Rats Learned to Drive—and They Love It

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    THIS ARTICLE IS republished from The Conversation under a Creative Commons license.

    We crafted our first rodent car from a plastic cereal container. After trial and error, my colleagues and I found that rats could learn to drive forward by grasping a small wire that acted like a gas pedal. Before long, they were steering with surprising precision to reach a Froot Loop treat.

    As expected, rats housed in enriched environments—complete with toys, space, and companions—learned to drive faster than those in standard cages. This finding supported the idea that complex environments enhance neuroplasticity: the brain’s ability to change across the lifespan in response to environmental demands.

    After we published our research, the story of driving rats went viral in the media. The project continues in my lab with new, improved rat-operated vehicles, or ROVs, designed by robotics professor John McManus and his students. These upgraded electrical ROVs—featuring ratproof wiring, indestructible tires, and ergonomic driving levers—are akin to a rodent version of Tesla’s Cybertruck.

    As a neuroscientist who advocates for housing and testing laboratory animals in natural habitats, I’ve found it amusing to see how far we’ve strayed from my lab practices with this project. Rats typically prefer dirt, sticks, and rocks over plastic objects. Now, we had them driving cars.

    But humans didn’t evolve to drive either. Although our ancient ancestors didn’t have cars, they had flexible brains that enabled them to acquire new skills—fire, language, stone tools, and agriculture. And some time after the invention of the wheel, humans made cars.

    Although cars made for rats are far from anything they would encounter in the wild, we believed that driving represented an interesting way to study how rodents acquire new skills. Unexpectedly, we found that the rats had an intense motivation for their driving training, often jumping into the car and revving the “lever engine” before their vehicle hit the road. Why was that?

    The New Destination of Joy

    Concepts from introductory psychology textbooks took on a new, hands-on dimension in our rodent driving laboratory. Building on foundational learning approaches such as operant conditioning, which reinforces targeted behavior through strategic incentives, we trained the rats step-by-step in their driver’s ed programs.

    Initially, they learned basic movements, such as climbing into the car and pressing a lever. But with practice, these simple actions evolved into more complex behaviors, such as steering the car toward a specific destination.

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  • The Earth Will Feast on Dead Cicadas

    The Earth Will Feast on Dead Cicadas

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    Much like an unexpected free dinner will distract you from the leftovers sitting in your fridge, this summer’s cicada emergence will turn predators away from their usual prey. During the 2021 Brood X emergence, Zoe Getman-Pickering, a scientist in Lill’s research group, found that as birds swooped in on cicadas, caterpillar populations exploded. Spared from birds, caterpillars chomped on twice as many oak leaves as normal—and the chain of effects went on and on. Scientists can’t possibly study them all. “The ecosystem gets a swift kick, with this unexpected perturbation that changes a lot of things at once,” says Louie Yang, an ecologist and professor of entomology at UC Davis.

    From birth to death, these insects shape the forest around them. As temperatures rise in late April, pale, red-eyed cicada nymphs begin clawing pinky-sized holes in the ground, preparing for their grand May entrance. All of these tunnels make it easier for rainwater to move through the soil, where it can then be used by plants and other dirt-inhabiting microbes. Once fully grown and aboveground, adult cicadas shed their exoskeletons, unfurl their wings, and fly off to spend their remaining four to six weeks on Earth singing (if they’re male), listening for the sexiest songs (if they’re female), and mating.

    Mother cicadas use the metal-enhanced saws built into their abdomens—wood-drilling shafts layered with elements like aluminum, copper, and iron—to slice pockets into tree branches, where they’ll lay roughly 500 eggs each. Sometimes, all of these cuts cause twigs to wither or snap, killing leaves. While this could permanently damage a very young sapling, mature trees simply shed the slashed branches and carry on. “It’s like natural pruning,” Kritsky says, which keeps hearty trees strong, prevents disease, and promotes flower growth.

    Once mating season winds down, so does the cicada’s life. “In late summer, everybody forgets about cicadas,” Lill says. “They all die. They all rot in the ground. And then they’re gone.” By late June, there will be millions of pounds of cicadas piling up at the base of trees, decomposing. The smell, Kritsky says, “is a sentient memory you will never forget—like rancid Limburger cheese.”

    But these stinky carcasses send a massive pulse of food to scavengers in the soil. “The cicadas serve as reservoirs of nutrients,” Yang says. “When they come out, they release all this stored energy into the ecosystem,” giving their bodies back to the plants that raised them. In the short term, dead cicadas have a fertilizing effect, feeding microbes in the soil and helping plants grow larger. And as their remnants make their way into woodland ponds and streams, cicada nutrients are carried downstream, where they may strengthen aquatic ecosystems far beyond their home tree.

    They may smell like bad hamburgers, but Yang says that if you’re lucky enough to host a tree full of cicadas this year, it’s best to just leave their bodies alone to decompose naturally. “They’ll be gone soon enough,” he says. If the pileup is especially obtrusive, simply sweep them out of the way and let nature do the rest.

    The thought of billions of screeching insects in your backyard might make your skin crawl, but you don’t need to be a passive observer when they arrive. Researchers are clamoring for citizen scientists to send in photos of their local cicadas to help map the upcoming emergence. The Cicada Safari app, developed by Kritsky, received and verified 561,000 cicada pics during the 2021 Brood X emergence—he hopes to get even more this time around.

    “This is an amazing natural phenomenon to wonder about,” Lill says, “not something to be afraid of.”

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