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Flying squirrel

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Flying squirrels are a large tribe of animals known as Pteromyini. This group includes 50 different species within the squirrel family, Sciuridae. Although their name suggests they can fly, they do not fly like birds or bats. Instead, they use a specialized method called gliding to move between trees.

Gliding flying squirrel
Gliding flying squirrel

This ability allows them to travel through forest environments with great speed and efficiency.

The mechanics of gliding rely on a unique body part called a patagium. The patagium is a furry skin membrane that stretches from the squirrel's wrist to its ankle. To control this membrane, flying squirrels have a specialized piece of cartilage at the wrist. This cartilage, known as the styliform cartilage, is unique to flying squirrels and not found in other gliding mammals. By holding this cartilage upward, the squirrel creates a wing tip. This wing tip can adjust to different angles to manage aerodynamic movements.

Glaucomys volans 1zz
Glaucomys volans 1zz

The squirrel also uses its wrist to change how tight the patagium is during flight.

Stability during a glide is provided by the squirrel's tail. The tail is flattened from the back to the front, which scientists call dorsoventrally flattened. This shape helps the animal control the air around it as it moves. The tail also functions as an adjunct airfoil. When the squirrel approaches a tree, it uses its tail as an air brake to slow down. This process allows the squirrel to create a large glide angle. By increasing air resistance, the squirrel decreases its velocity for a safer landing. All four limbs can then absorb the impact of hitting the tree trunk.

Evolutionary studies have helped clarify how these animals developed. Molecular studies show that flying squirrels are monophyletic. This means they all share a common ancestor and have no non-flying descendants. These studies suggest they originated approximately 18 to 20 million years ago. The earliest known lineage is the genus Paracitellus, which dates back to the late Oligocene era. Flying squirrels have a close sister relationship with tree squirrels. Because of this close ancestry, scientists can study how their physical differences led to the development of gliding.

To improve maneuverability, flying squirrels have developed specific bone proportions. Compared to squirrels of a similar size, they have longer forearm bones and longer lumbar vertebrae. However, their hand bones, foot bones, and distal vertebrae are shorter. These adaptations help minimize wing loading during flight. Because of these changes, flying squirrels are not as well adapted for walking on four legs as regular squirrels. Instead, they rely heavily on their ability to glide. This lifestyle offers several advantages for survival. Gliding is an energetically efficient way to forage for food across large areas. It also helps them avoid predators by allowing them to escape from one tree to another quickly.

There is a wide variety of flying squirrel genera across the world. New World flying squirrels belong to the genus Glaucomys, which means "gleaming mouse" in Greek. This includes the Northern flying squirrel and the Southern flying squirrel. Old World flying squirrels belong to the genus Pteromys, or "winged mouse." The Siberian flying squirrel is an example that lives in parts of Russia, Finland, and Estonia. In Southeast Asia, there are many other types, such as the giant flying squirrels of the genus Petaurista. Several new species of these giant squirrels were discovered in Arunachal Pradesh, India, during the late 2000s.

Flying squirrel in a tree
Flying squirrel in a tree

Most flying squirrels are nocturnal, meaning they are active during the night. They are also omnivores with a very diverse diet. They eat plant matter like fruit, seeds, buds, flowers, and tree sap. They also consume animal matter, including insects, spiders, gastropods, fungi, and even bird eggs.

Glaucomys volans 1zz
Glaucomys volans 1zz

The life cycle of a flying squirrel begins in a nest. Young squirrels are born naked and helpless. They rely on their mothers for care until they are five weeks old. At that age, they begin practicing their gliding skills. By ten weeks of age, they are fully ready to leave the nest and live on their own.

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🖼️ Images & Media (3)
File:Flying squirrel in a tree.jpg
Flying squirrel in a tree.jpg
File:Glaucomys volans 1zz.jpg
Glaucomys volans 1zz.jpg
File:Gliding flying squirrel.jpg
Gliding flying squirrel.jpg
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