35 Interesting Facts About Squirrels

1. Squirrels are small or medium-sized rodents present in all inhabited continents except Australia. Their closest relatives are mountain beaver and dormouse.
2. The name squirrel derives from the Greek word skiouros, which means “shade tail.”
3. There are more than 260 known species of squirrels in 50 genera. The most common are tree squirrels, with over 120 species in 22 genera.
4. Other well-known squirrels include ground squirrels, flying squirrels, chipmunks, marmots, and prairie dogs.
5. Squirrels initially appeared on earth around 36 million years ago in western North America. Later they migrated to Europe (30 mya), Africa (20 mya), and Southeast Asia (11 mya). (Source)
6. Unlike most other mammals, tree squirrels can descend from the tree head-first. They can do so by rotating their hind limbs 180 degrees. They also get a strong grip thanks to their sharp claws.
7. Squirrels use their tails for defensive purposes against rattlesnakes. They heat their tails through infrared radiation. These radiations are invisible to the human eye but can be sensed by rattlesnakes. (Source)
8. The African pygmy squirrel is the smallest species, with a length of just 5 inches from nose to tail. The Indian giant squirrel is the largest squirrel that is 3 feet long. Various species can weigh from 0.5 ounces to 4 pounds.
9. Flying squirrels live in nests and tree holes. They can glide in the air from one tree to another by extending their forelimbs and hind limbs. They can cover more than 150 feet distance in a single gliding leap.

   

   Flying squirrels are the only nocturnal squirrel species

   
   
10. Unlike other rodents, squirrels are predominantly diurnal. Only flying squirrels are known as nocturnal (active at night).
11. Ground squirrels live in burrows or tunnel systems. Few species of ground squirrels hibernate in the winter season.
12. Most squirrel species do not hibernate and store food for winter. But the 13-lined ground squirrels hibernate for eight months in a year. They can hibernate for this long period without eating or drinking anything, thanks to low serum concentration in their bodies. (Source)
13. Hibernating ground squirrels experience the same reduced blood flow to the brain as seen in stroke patients. However, they can overcome this issue without facing any ill effects. This discovery has increased the chances of better stroke treatments in humans. (Source)
14. Squirrels are omnivores. Their diet includes nuts, fruits, seeds, insects, eggs, and baby birds. Few species of tree squirrels eat tree sap as a delicacy.
15. Squirrels have excellent focusing power and a wide-angle dichromatic vision. Their hearing frequency is between 113 Hz and 49 kHz, far higher in range than a human’s hearing range. Male squirrels locate receptive females through their scents. Squirrels also have a good sense of touch. They can detect vibrations through sensitive hairs on different parts of their body. (Source)
16. Like other rodents, squirrels’ teeth grow throughout their lives. They keep the growth of their teeth in check by chewing hard objects, like acorns and hard-shelled nuts.
17. Squirrels have long bushy tails, almost the length of their body. It performs several functions such as keeping balance while moving from one tree to another, and acts as a parachute if a squirrel falls from a tree. Tails also keep their bodies warm in winter and cool in the summer season. It also acts as a communication device during a mate and while facing a predator. (Source)
18. Various squirrel species can swim for short distances. Most of them use their tail for assistance. They usually swim to avoid predators or when searching for a new home. 
19. Squirrels live in every environment with vegetation. Few species have adapted to live in urban and suburban areas in the company of humans.
20. Female squirrels can give birth several times a year. There are usually 2 to 8 offspring in a litter. Newborn squirrels are deaf, blind, and naked (without fur). 
21. Squirrels are known to attack and kill large animals in case of scarcity of food. In 2005, a pack of black squirrels killed and consumed a stray dog in Russia. They are also known to attack birds’ nests for food. (Source)
22. Squirrels have a unique behavior of burying nuts before the start of the winter season. They lose around 25% of their buried nuts to thieves (a few birds and animals). Squirrels create false caches or hide them in difficult-to-reach positions to save them from thieves. However, they fail to recover a large number of their buried nuts. These misplaced nuts assist in the growth of trees. (Source)
23. In 2007, Iran “arrested” 14 squirrels for spying. They claimed that these small mammals were carrying spy gear from foreign agencies. (Source)
24. Squirrels can jump very high and far. It is due to their powerful hind legs, which are larger than their forelimbs. Their forelimbs contain four digits and a thumb, while the hind limbs have five toes.
25. In the 2005 movie “Charlie and the Chocolate Factory,” forty real squirrels were used to act in the Nut Room scene. (Source)
26. Squirrels run zigzags to avoid birds of prey and other predators. But the same running style makes them vulnerable to cars. (Source)
27. Trees such as pine, true firs, spruces, and larches depend heavily on truffles for survival. Various types of squirrels, especially flying squirrels, play a vital role in the growth of truffles. (Source)

    

    Squirrels play vital role in the growth of truffles

    
    
28. A study shows that squirrels modify their behavior according to birdsong. These rodents become watchful after hearing an alarming call from birds. On the other hand, squirrels become calm after a non-alarm-making bird call. (Source)  
29. After storms, wildlife is the second major cause of power failures in the USA. Half of the total power outages by animals are caused by squirrels. (Source)
30. Few species of ground squirrels use rattlesnake’s scent to reduce predation risks. These squirrels chew the shed skin of rattlesnakes and lick it on their fur for protection. (Source)
31. Few people believe squirrels can predict the harshness of the winter season through the height of their nests. However, this myth has no scientific basis.
32. Squirrels are generally harmless, but can attack humans on occasions. They can even cause severe injury during these attacks. (Source)
33. Squirrels can transmit a few diseases to humans. The most common one is squirrel pox. They also carry leprosy germs, but their transmission of infection to humans has not been proven. (Source)
34. The fine fur of squirrels was used for clothing during the medieval period. A study proves that this fur could be a reason for the spread of leprosy in the middle ages. (Source)
35. Tree squirrels bury their nuts separately according to their size, type, weight, and nutrition. It assists them to remember the location of similar nuts. (Source)