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TEKS: Science: 3.3C, 4.3C, 5.3C, 5.9A, 6.3D; ELA: 3.12A, 4.12A, 5.12A, 6.11A


Nutty Behavior

How do squirrels organize the nuts they find?

RYAN HOANG/UC BERKELEY

Mikel Delgado gives a squirrel a nut to see where the critter will store it.

RYAN HOANG/UC BERKELEY

Squirrels are busy little creatures. You’ve probably seen them scampering up trees and hopping across lawns. The rodents are most active in the fall, collecting nuts to eat over the winter.

Squirrels bury their nuts in the ground. That keeps them hidden from other animals that might eat them. But squirrels have to remember where the nuts are buried so they can recover them later. “It’s an interesting problem,” says Mikel Delgado. She’s
an animal behavior expert at the University of California, Davis.

Delgado wanted to know if there’s any pattern in the way squirrels bury their nuts. She set out to investigate the question.

Squirrels are busy little creatures. You’ve likely seen them scurrying up trees. Or you’ve seen them hopping across lawns. The rodents are most active in the fall. That’s when they collect nuts to eat over the winter.

Squirrels bury their nuts in the ground. That keeps them hidden from other animals that might eat them. But squirrels have to remember where nuts are buried. Then they can recover them later. “It’s an interesting problem,” says Mikel Delgado. She’s an animal behavior expert. She works at the University of California, Davis.

Delgado wondered if there’s any pattern to how squirrels bury their nuts. She set out to investigate the question. 

Going Nuts

Delgado and a team of researchers gave 45 wild squirrels in Berkeley, California, four kinds of nuts: almonds, hazelnuts, pecans, and walnuts.

The team then watched the squirrels to see where they buried the nuts. They used a handheld GPS tracker—a device that uses satellites to track objects on Earth—to record each nut’s location. The team used that data to make a map showing where each nut was buried. 

Delgado worked with a team of scientists. They chose four kinds of nuts. They included almonds, hazelnuts, pecans, and walnuts. They gave them to 45 wild squirrels in Berkeley, California.

The team then watched the squirrels. They wanted to see where they buried the nuts. They used a handheld GPS tracker. This device uses satellites to track objects on Earth. The GPS recorded each nut’s location. The team used that data to make a map. It showed where each nut was buried. 

PETER DASILVA

A researcher uses a detector to search for buried hazelnuts (inset), which contain a trackable microchip.

Keeping Track

Delgado found that squirrels didn’t just bury nuts randomly. They hid them in different spots depending on what type they were. For example, squirrels put almonds in one place and walnuts in another. Delgado thinks the behavior might help squirrels remember where to find their meals.

Delgado found that squirrels didn’t bury nuts randomly. They hid them in different spots based on what type they were. Squirrels put almonds in one place, for example. They put walnuts in another. Delgado thinks the behavior might help squirrels. They can better remember where to find their meals. 

ROLF NUSSBAUMER/NPL/MINDEN PICTURES

In a related study, Delgado set out to learn what happened to the nuts over time. She gave squirrels nuts containing microchips. (Hungry squirrels could eat the nut around the chip.) Delgado’s team used a detector to track the buried nuts. She found that squirrels often move nuts from place to place. She’s not sure why.

“Animals do so many cool things that we don’t realize,” Delgado says.  

Delgado ran another study. It set out to learn what happened to the nuts over time. She gave squirrels nuts with microchips inside. (Hungry squirrels could eat the nut around the chip.) Delgado’s team used a detector. It tracked the buried nuts. She found that squirrels often move nuts from place to place. She’s not sure why.

“Animals do so many cool things that we don’t realize,” Delgado says.  

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