2024-06-14 by Shakunthala Natarajan

Why Do Some Squirrels Bury Nuts? | Science Blog

It is a nice windy Autumn day in the forest grounds close to the cold Arctic regions. It is one of those last few days of warmth before the freezing cold sets in. Sensing the favourable weather, a proactive squirrel is deeply engrossed in finding good nuts for his meal. The tiny visitor is busy searching for food. He gets excited as he finds a large yummy nut tucked between the leaves on the ground. But you see that he tries to bury the nut instead of relishing it! Are you wondering why a squirrel buries the nut he finds? Are you one of those Animal Planet enthusiasts fascinated with ‘Animal behaviour studies and exploration’? Then let us team up with Utsuka and Jigyasa in this episode of IndiAsksWhy, as they embark on this wonderful jaunt into the wild.

Looking at the squirrel nut burying trait, you must first be curious to know who taught these tiny beings, ‘the art of burying nuts’. You will be surprised to learn that no one has taught these clever squirrels this art! Behavioural scientists have found that the lab-born squirrels as well as the squirrels in the wild, both bury specific nuts that are given to them. Hence this behaviour is inborn with the squirrels. Such traits are referred to as ‘innate traits’ and are present naturally in an organism. Moving on, do you know that the nut stashing trait is commonly found in cold country squirrels? It is extremely difficult for them to find food supplies in the freezing winter months! So they are proactive, collect and bury nuts for the winter time during the nice and breezy autumn days. But these tiny beings are extremely smart. They create some sort of a mental landmark of the secret nut godowns in their brains! Sometimes if the squirrels sense that they are being watched, they fake up or act like burying the nut at a place, to misguide their opponents!

You might be wondering, why do squirrels protect their nuts so much. Well, although they consume insects, and are omnivores, nuts are their largest sources of nutrition. Moreover, ‘nut theft’ is prevalent in the squirrel community :(. So they give it their all to protect their prized future food! Now you must be wondering, how do these squirrels manage to get back to their nut stores. How are they able to trace back their trails? Do they throw bread crumbs all the way to make a trail to their nutty store, like Hansel and Gratel :)? Nope! Our tiny friends have an amazing sense of memory, orientation of their surroundings, and a great smelling capacity. This is akin to having an in-built GPS device coupled with a smell detector! These qualities carry them to their buried food.

But the story does not end there. These smart creatures also have a food quality assessment system in place! This check system has two main components - ‘paw feel’ and ‘head flick’. The nut is first rolled between the paws to detect any cracks or blemishes that indicate it is damaged. After passing this first level of checks, the nut is held in the mouth of the squirrel. Now the squirrel makes a slight head movement causing the nut inside the shell to roll. With this, it tests if the shell actually has a nut or is empty and also gets a rough estimate of the nut’s weight! This discretion helps them decide what kind of nuts to bury and which ones to immediately consume for a hearty meal.

But do you think that this nut stashing trait is universal in the squirrel population? No. Squirrels living in hot and tropical regions have good access to food supplies throughout and experience milder climatic conditions. So there is no need for them to save up their food for later. Now you must be asking, ‘what will happen to the cold country squirrels when they are moved to tropical regions?’. To understand such innate animal traits better, let us join Utsuka and Jigyasa for a conversation with wildlife scientist, Dr Karthikeyan Vasudevan. Dr Vasudevan explains that innate behaviours are naturally present in an organism. These behaviours are active in an organism based on its developmental stage, needs and survival necessities. Most importantly, he says that an organism’s surroundings also shape its behavioural patterns and traits. For instance, abiotic factors like temperature, biotic factors like presence of food resources, constraints like predators and mating factors, significantly impact an organism’s traits. These traits in turn aid in the organism’s survival.

We have now come to an end of our tour in the world of squirrels across different regions in the globe. We saw that squirrels in cold regions stash up their nuts for the winters. We also got to unravel the secrets behind the nut sensing system and food detection system in place in these squirrels! Finally we understood some factors that shape and influence animal behaviour. I bet, by now, you must be captivated by the intelligence displayed by the tiny squirrels and want to know more about them directly from Utsuka and Jigyasa. So, it is now time to gear up your headphones, listen to the podcast and start your Science quest. Happy learning!!!

References

Allen, J. (2017) Squirrels actually organize their nut hoard - here’s why, HowStuffWorks. Available at: https://animals.howstuffworks.com/mammals/squirrels-really-organize-nuts.htm (Accessed: 06 August 2023). Ben EsmanBen has a bachelor’s degree in construction engineering. When not constructing or remodeling X-Ray Rooms (2022) Why do squirrels bury nuts? (and why some squirrels don’t), My Backyard Life. Available at: https://mybackyardlife.com/why-do-squirrels-bury-nuts/ (Accessed: 06 August 2023). Blog archives (no date) Squirrel Gazer. Available at: https://www.squirrelgazer.com/blog/archives/01-2019(Accessed: 06 August 2023). Bryce, E. (2018) How do squirrels remember where they buried their nuts?, LiveScience. Available at: https://www.livescience.com/64104-how-do-squirrels-find-buried-nuts.html (Accessed: 06 August 2023). Griffin, A. (2018) In the autumn, squirrels think about nuts so much that it may make their brains bigger, Quartz. Available at: https://qz.com/1462091/how-do-squirrels-find-their-nuts-in-the-winter (Accessed: 06 August 2023). Morris, P. (2022) How do squirrels find their nuts?, BBC Wildlife Magazine | Discover Wildlife. Available at: https://www.discoverwildlife.com/animal-facts/mammals/how-do-squirrels-find-their-nuts/ (Accessed: 06 August 2023).

Cover Image Credit: Image by Jon Pauling from Pixabay