Buzz
1. Unique Physical Features
Squirrels, in general, are small animals with a wide range of sizes. For example, the African pygmy squirrel is only 12–14 cm long and weighs just 15–18 g, while the Indian giant squirrel can reach 25–50 cm in body length, with a tail as long or even longer, and weigh between 1.5–2 kg (rarely up to 3 kg). Squirrels typically have slender bodies with bushy tails and large eyes. Their fur is soft and smooth, although in some species, it may be thicker. Fur color varies significantly between species and even within the same species.
Their hind legs are generally longer than their front legs, and each leg has four or five toes. The front legs have a thumb, though it is underdeveloped. Additionally, the soles of their feet are soft.
Squirrels can be found in almost every habitat, from tropical rainforests to semi-arid deserts, though they are absent from polar regions and the driest deserts. They are primarily herbivores, feeding on nuts and fruits, but some species also consume insects and even small vertebrates. In fact, some tropical species almost exclusively eat insects. Squirrels have a typical rodent dental structure, with large incisors designed for gnawing, which grow throughout their lives, and molars positioned far apart for grinding food.
Most squirrel species have excellent vision, which is particularly important for tree-dwelling species. Many also have sensory systems with whiskers or specialized hairs on their legs.
Squirrels breed one to two times per year, with litter sizes varying between species, typically after 3–6 weeks of gestation. Newborn squirrels are born hairless, toothless, blind, and fragile. In most species, the mother is the sole caretaker of the young, feeding them until they are 6–10 weeks old. By the end of their first year, they reach sexual maturity. Ground-dwelling species tend to be more social and live in groups, while tree squirrels are mostly solitary.
2. Feeding Habits and Reproduction of Squirrels
Squirrels are primarily herbivores, feeding on nuts and fruits, but many species also consume insects and even small vertebrates. In fact, some tropical species almost exclusively eat insects. Squirrel teeth follow a typical rodent pattern, with large incisors that grow continuously throughout their lives for gnawing, and large gaps between the incisors and the molars, which are used for grinding food.
Squirrels generally have excellent vision, which is especially important for those living in trees. Many species also have highly developed sensory systems, including whiskers and specialized hairs on their legs.
Most squirrel species reproduce once or twice a year, with the number of offspring varying between species after a gestation period of 3-6 weeks. Newborn squirrels are born hairless, toothless, blind, and weak. In most species, only the mother cares for the young. They are nursed for about 6-10 weeks and reach sexual maturity by the end of their first year. Ground-dwelling squirrels are usually social and live in groups, while tree squirrels tend to be solitary.
If their nests are threatened by predators or disturbed by humans, a mother squirrel will quickly relocate her young to a safer location and may even build a new nest in a different area.
3. The Flying Squirrel Can Glide Up to 90 Meters
The Glaucomys volans, commonly known as the flying squirrel, lacks wings but can glide through the air like a glider, skillfully navigating the skies. However, witnessing this spectacle is rare, as flying squirrels are nocturnal and only display their remarkable agility at night. During the day, they hide in burrows or tree nests, occasionally taking over abandoned nests of tree squirrels, woodpeckers, or other birds to call their own. Inside these nests, they craft a comfortable bed using soft tree bark, moss, lichen, and fur.
The mating season for the Glaucomys volans occurs between February and March. After a 40-day pregnancy, the female gives birth to a litter of 2 to 6 babies in a cozy nest. The young are nursed for 10 weeks and must reach a sufficient size before they can glide from tree to tree.
Adult male flying squirrels measure about 25 cm in body length, with tails around 12 cm long and weigh approximately 79 grams. With a single glide, they can travel distances of up to 90 meters. Their “wings” are actually skin membranes stretched between their limbs, from the neck to the ankles. While gliding, they extend all four limbs to open this membrane. Flying squirrels primarily search tree tops for fruits, tree bark, lichen, and mushrooms. They only take flight when threatened by predators like owls or other carnivores.
Flying squirrels also eat insects, bird eggs, and small animals. When not raising young, they tend to live alone in their nests. However, they often gather in large groups when food is abundant. In the fall, they store food in tree cavities to prepare for the winter. Though they do not hibernate, they become less active and slower in colder months.
4. Squirrels Use Shed Snake Skin to Fool Their Enemies
A researcher from the University of California, UC Davis, made an intriguing discovery: squirrels use shed snake skin to deceive their predators. According to a recent study by UC Davis, ground squirrels and California rock squirrels have been observed cleverly masking their scent by chewing up rattlesnake skin and applying it to their fur.
Barbara Clucas, a graduate student in animal behavior at UC Davis, conducted observations of these “master tricksters” – the ground and rock squirrels – as they collected dried snake skins, chewed them into a pulp, and smeared the mixture onto their fur.
Clucas revealed that female squirrels and young ones are more likely to use this tactic than adult males. This is because adult males, being more experienced, are less susceptible to being intimidated by snakes. The scent of the snake helps the squirrel cover its own scent, especially when they are resting or sleeping at night, or to send a signal saying: “Hey, there’s a snake in the hole.”
Squirrels don’t just use dried snake skin; they also collect the smell of rocks or places where snakes have been, using these scents to mask their presence. Other rodents also engage in similar behaviors. Using snake scent is a clever defense mechanism against rattlesnakes, as squirrels can heat up their tails to send a warning signal to rattlesnakes, which can detect heat through infrared vision. The squirrels gauge the danger level of the snake by its sound and display a determined attitude to deter the snake from attacking.
5. The Red Squirrel Is on the Brink of Extinction
A recent study by British scientists reveals alarming news: the red squirrel is set to become extinct within the next 20 years. According to research conducted by scientists at Oxford University, the red squirrel population has declined by more than 50% over the past 50 years due to rapid urban development, failed conservation efforts, and competition from the grey squirrel. If current trends continue, we will soon no longer see red squirrels in the wild.
The red squirrel, also known as the Eurasian squirrel, is an omnivorous tree-dwelling animal that belongs to the Sciurus genus. Its body length ranges from 19 to 23 cm, and it weighs between 250 and 340 grams.
In addition to the red squirrel, other species like the European hedgehog, the hazel dormouse, wild rabbits, and wildcats are also facing the threat of extinction. The European hedgehog's population has dropped dramatically, from 30 million in the 1950s to just 15 million today, according to the Wildlife Conservation Society at Oxford University.
While many mammal species in Britain have seen a significant decline over the past 25 years, some, like field mice and otters, have managed to stabilize or even increase in numbers in recent decades.
6. Squirrels Can Be Toxic
Like other wildlife species, squirrels that have been exposed to high levels of pollution or toxic waste can pose health risks to humans. In 2007, the New Jersey Department of Health issued a warning for anyone consuming squirrels (particularly children and pregnant women) to limit consumption after a lead-contaminated squirrel was found near the Ringwood Mines landfill in New Jersey.
Toxic waste had been illegally dumped at this location for years before the authorities cracked down on the practice in the 1980s. Hunting and eating squirrels has long been a tradition among many Native American communities.
In 1997, doctors in Kentucky raised concerns about the dangers of eating squirrel brains, a local delicacy in some areas. In the western U.S., physicians observed a high incidence of Creutzfeldt-Jakob disease, a rare and fatal neurodegenerative disorder that causes memory loss and eventually leads to death. This so-called "mad squirrel disease" can be difficult to distinguish from typical squirrel behavior but is more commonly found in animals that have been struck by vehicles. Some people have special rituals for preparing and eating squirrel brains, while others avoid it altogether.
7. Birth Control for Grey Squirrels
To slow the explosive population growth of grey squirrels, which are notorious for destroying trees and crops, American scientists have come up with an unusual solution: lacing seeds with contraceptives. With milder winters and an abundance of acorns, the number of grey squirrels has surged across several U.S. states. While they may appear cute, these squirrels are, in fact, notorious pests, stripping bark from trees, gnawing on power lines, and ravaging farmland.
To control their numbers, researchers are focusing on managing their reproduction. However, convincing squirrels to take birth control voluntarily is no easy task. The current contraceptive pills are far too large for their mouths, making this approach unfeasible.
Scientists are considering two options: using a vaccine to prevent the production of reproductive hormones, or lowering their cholesterol levels, since cholesterol is essential for hormone production. The major advantage of the vaccine is that one shot can provide long-term effects, potentially for years. However, capturing and injecting the squirrels presents significant challenges.
Before suggesting DiazaCon, the team studied its effects on grey squirrels for nearly a decade. They lost over 100 trees due to the squirrels' bark-stripping habits and spent over a million dollars on planting, maintaining, and removing trees damaged by them. The researchers began lacing sunflower seeds, one of the squirrels' favorite foods, with DiazaCon at 16 locations on the Clemson University campus.
The seeds were dyed pink to indicate they had been treated, but the squirrels paid no mind. The team plans to continue distributing the laced seeds next year while monitoring the squirrels' behavior and reproduction to assess the effectiveness of the contraceptive. They will also monitor any potential side effects on the squirrels and any predators that may consume them.
8. Top 5 Squirrel Species Facing Extinction in Vietnam's Red List
Vietnam's Red List of endangered species includes animals facing varying levels of threat, with some found exclusively in Vietnam. Among these are several squirrel species at risk of extinction in both Vietnam and worldwide. Below are the top 5 endangered squirrel species in Vietnam:
1. **Eared Flying Squirrel (Belomys pearsonii)**: A rare mammal in the squirrel family, first described by Gray in 1842. This species is primarily found in Vietnam and is critically endangered.
2. **Small Flying Squirrel (Hylopetes phayrei)**: Also known as Phayre's Flying Squirrel, it inhabits regions of China, Laos, Myanmar, Thailand, and Vietnam. It was first described by Blyth in 1859.
3. **Starred Flying Squirrel (Petaurista elegans)**: Found in China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, and Vietnam, this species is becoming increasingly rare.
4. **Black Giant Squirrel (Ratufa bicolor)**: A large tree squirrel species found in forests across northern Bangladesh, northeastern India, eastern Nepal, Bhutan, southern China, Myanmar, Laos, Thailand, Malaysia, Cambodia, Vietnam, and western Indonesia.
5. **Red Squirrel (Sciurus vulgaris)**: Native to Eurasia, the Red Squirrel has been decreasing rapidly, especially in the UK and Ireland, due to the introduction of the Eastern Grey Squirrel (Sciurus carolinensis) from North America. Recent studies indicate a rapid decline in their population.
9. Fascinating Facts About Squirrels
Here are some fascinating facts about squirrels:
- In Greek, the word “squirrel” means “shadow tail.”
- One of the most characteristic behaviors of squirrels is hoarding nuts and acorns for winter. This is essential since squirrels do not hibernate.
- Squirrels have incredibly flexible hind legs, allowing them to climb up and down trees with great speed.
- A male squirrel can smell a female squirrel from up to a mile (1.6 km) away.
- The squirrel mating season runs from February to May, with a gestation period of 44 days. Female squirrels give birth to 2-4 young per litter.
- Squirrels have four sharp claws on their front paws that help them cling tightly to tree bark when climbing. Each foot has five distinct toes.
- In addition to their natural habitat in the eastern United States, Eastern Grey Squirrels are also found in many Western states, as well as in the UK, Ireland, and South Africa.
- With 285 species, squirrels are found on every continent except Antarctica and Australia.
- Squirrels can consume up to their own body weight in food every week, approximately 1.5 pounds (0.8kg).
- Squirrels can fall from heights of up to 30 meters without injury.
- When jumping or falling from a height, squirrels use their tails to balance and act as a parachute!
- The Arctic Ground Squirrel is the only mammal known to survive freezing temperatures during hibernation.
- Squirrels have eyes placed on the sides of their heads, giving them a broad field of vision, even allowing them to see behind them.
- In 2007, Iran announced that 14 squirrels found near its border were actually “spy squirrels.”
- In 2013, authorities closed a campground in the Los Angeles National Forest after a squirrel infected with a disease killed a 15-year-old boy from Kyrgyzstan who tried to capture it. Over 100 people were quarantined due to possible exposure to the infected squirrel.
- Squirrels are incredibly smart and can learn to navigate obstacles to find the quickest path to food. They’re also quite good at discovering shortcuts.
- Squirrels can leap as far as 20 feet (6 meters). Their long, strong hind legs and coordinated front legs make these impressive jumps possible.
- In the 2005 remake of “Charlie and the Chocolate Factory,” the scene with squirrels picking hazelnuts wasn’t CGI, but real squirrels trained by animal trainer Michael Alexander. His team spent 19 weeks training the squirrels for that scene.
- In 1963, Longview, Washington, built a bridge called Nutty Narrows, making the town the capital of squirrel lovers in the U.S. Longview hosts an annual Squirrel Festival each August.
- Squirrels can run at speeds of up to 30 km/h, though most squirrels only reach about half that speed.
10. Overview of Squirrel Characteristics
Squirrels are generally small animals, with sizes ranging from 7 to 10 cm and weighing around 10 grams. Larger species can reach lengths of 50 to 75 cm and weigh between 5 and 8 kg. They have slender bodies, fluffy tails, large eyes, and sharp, curved claws.
Their fur is typically soft and smooth, with some species having denser coats. Squirrel fur colors vary, ranging from brown, gray, to red, depending on the species. Their hind legs are longer than their front legs, with each leg having four or five toes. The front paws have a thumb, though it is quite small, while the hind feet have soft soles. Their sharp claws help them cling to and climb tree branches with ease.
The squirrel’s tail serves multiple purposes, including maintaining balance, protecting them from rain and sun, and helping to keep their bodies warm.
General Characteristics:
- Common Name: Squirrel
- Scientific Name: Sciuridae
- Type: Mammal
- Diet: Omnivorous
- Size: 12-90 cm (depending on species)
- Weight: 0.5-1.8 kg
- Conservation Status: Not listed in the Red List
11. Squirrel Classification
Squirrels belong to the rodent order (Rodentia). Currently, there are around 50 genera and nearly 280 species of squirrels spread across 5 different subfamilies. There are many types of squirrels such as ground squirrels, tree squirrels, flying squirrels, and more. The scaly-tailed flying squirrel, found in Africa, belongs to the family Anomaluridae and is not a true squirrel from the Sciuridae family. Squirrels are found on nearly every continent except Australasia and Antarctica.
Some notable squirrel species include:
- Flying squirrels: Scientific Name: Pteromyini. These squirrels cannot fly for long distances but instead glide from tree to tree, with each flight covering around 90 meters. Their arms and legs help steer during their gliding, and their tails function not only to assist in flight but also as a brake to help them land safely.
- Rock squirrels: These small squirrels with bushy tails and brown-gray fur are commonly found in rocky areas in states like New Mexico, Texas, and Arizona. They live along cliff faces, caves, or highways, wherever food is available.
- Golden squirrels: Golden squirrels inhabit dense forests across North America, often foraging for food in berry bushes. Their diet consists of seeds, insects, and fungi.
- Eastern gray squirrels: Native to the Midwestern United States and Eastern Canada, these squirrels have gray fur, white bellies, and large, bushy tails.
- Red squirrels: Red squirrels are omnivorous and live on trees throughout Europe and Asia. Similar to the gray squirrel, they have white bellies, sharp, curved claws that help them climb, and their fur color can change depending on age and location.
Most squirrels around the world are omnivores, with a primary diet of nuts and fruits. However, some tropical species also consume insects and small vertebrates.
12. Key Differences Between Squirrel Species
The smallest squirrel species in the world is known as the African pygmy squirrel, measuring just 13 cm from nose to tail. In stark contrast, the largest squirrel species, found in India, can reach lengths of up to 90 cm.
Like other rodents, squirrels have four ever-growing incisors that they must continually gnaw to keep in check. Tree squirrels are among the easiest to identify, as they are commonly seen leaping from branch to branch. Another type of squirrel, the ground squirrel, typically lives in burrows or underground tunnel systems.
Ground squirrels primarily feed on nuts, leaves, roots, seeds, and other plant material. They also eat small animals like insects and caterpillars. These small squirrels must always remain on alert for predators since they are nearly defenseless. Occasionally, ground squirrels form groups and communicate danger by whistling to each other. Tree squirrels, on the other hand, are found in a variety of environments, from remote mountain forests to city parks. While these squirrels are excellent climbers, they often jump to the ground in search of food such as nuts, berries, fruits, and flowers. They also eat tree bark, eggs, and even young birds. Some species of tree squirrels have a particular fondness for tree sap.
The third type of squirrel is the flying squirrel, the most adaptable of all squirrel species. Like birds, flying squirrels live in nests or tree cavities. Though they cannot truly fly, they can glide great distances. When leaping from one tree to another, they spread their limbs and soar through the air. The flap of skin between their limbs and torso acts like wings, enabling them to glide up to 45 meters. In addition to nuts and fruit, flying squirrels also consume insects and even young birds.
