Sciurus

Many squirrels have big, bushy tails.

They live in many places. Some live in North America. Others live in Asia. They also live in South America. Some live in Europe too. Scientists study these small animals. They look at how the squirrels are related. They use tiny bits of life to help. This helps them group the animals. It is fun to learn about them.

Do you like squirrels?

Many squirrels have big, bushy tails. These squirrels belong to a group called Sciurus.

You can find them in many parts of the world. They live in North America and Europe. They also live in Asia and Central America. Some live in South America too.

Scientists study how these squirrels are related. They use a way of grouping called taxonomy. This helps them name each kind of squirrel. In 2005, experts said there were 28 species. A species is a specific type of animal.

Groups of squirrels can change over time. In 2015, experts looked at South American squirrels. They found new ways to group them. In 2020, a new study used genetic sampling. This means they looked at tiny bits of life. This study suggested many new groups. Some squirrels might move to new groups. For example, the Andean squirrel may move to a group called Leptosciurus. These small squirrels are called dwarf squirrels.

This is a type of Sciurus squirrel.

The genus Sciurus includes many common squirrels. You might see them in your yard. Most have big and bushy tails. These animals live in many different places. They are found in North America and Europe. They also live in Asia and Central America. Some live in South America as well.

Scientists use a way of grouping called taxonomy. This helps them name every type of squirrel. The number of species can change often. In 2005, experts Thorington and Hoffman studied them. They accepted 28 different species in this group. This list included many different names. It included the Eastern gray squirrel and the Eurasian red squirrel.

Grouping animals is a hard job for scientists. In 1914, Joel Asaph Allen tried to split the group. His attempt was not very satisfying to others. Later, de Vivo and Carmignotto did a big review. They looked at South American squirrels in 2015. They looked at them for the first time in many decades. They changed many names and split some species.

New tools help scientists learn more today. In 2020, a paper studied the taxonomy of Sciurinae. This is the group of squirrels. The scientists used genetic sampling. This means they looked at tiny bits of life. They looked at almost all recognized species. This study suggested many new groups for the squirrels. It suggested moving the Andean squirrel to a new genus called Leptosciurus.

These small squirrels are called dwarf squirrels. The 2020 study also looked at the Red-tailed squirrel. It suggested moving that squirrel into a group called Syntheosciurus. Some squirrels might still move to new groups later. For example, the study might change where Sciurus deppei goes. This work shows how much we can learn. We are still discovering how these living things fit together.

The genus *Sciurus* contains many of the bushy-tailed squirrels we see every day. These animals are found across several large parts of the world. They live in North America and Europe. They also inhabit temperate Asia, Central America, and South America. Scientists study these animals to understand how different species are related. This process of naming and grouping is called taxonomy. Taxonomy helps us organize the massive variety of life on Earth. Because new information is always being discovered, the exact number of species in *Sciurus* often changes.

Taxonomy can be a very complex process for scientists. In 2005, researchers Thorington and Hoffman provided a specific interpretation of the genus. They accepted 28 different species within the *Sciurus* group. Their list included many well-known animals like the Eastern gray squirrel (*Sciurus aureogaster*). It also included the Eurasian red squirrel (*Sciurus vulgaris*). This list was organized into several subgenera, which are smaller groups within a larger genus. These subgenera included names like *Sciurus*, *Otosciurus*, *Guerlinguetus*, *Tenes*, *Hadrosciurus*, and *Hesperosciurus*. Each subgenus contained different types of squirrels found in specific regions.

History shows that scientists have long debated how to group these squirrels. In 1914, Joel Asaph Allen attempted to split the genus into different parts. He tried to raise several South American subgenera to the rank of full genus. He also tried to merge *Urosciurus* into *Hadrosciurus*. However, his work was considered unsatisfying by many other experts. Later, in 2015, de Vivo and Carmignotto conducted a massive review. They looked at South American squirrels for the first time in many decades. They changed many names by synonymizing some species and splitting others. This review suggested that only 15 to 17 species actually belonged in the *Sciurus* genus.

Modern technology has changed how we classify these animals. In 2020, a new paper focused on the taxonomy of the Sciurinae group. This group includes all the squirrels in this family. The researchers used genetic sampling to study the animals. Genetic sampling involves looking at the DNA to find similarities between species. They were able to sample almost all recognized species. This study recommended many new assignments for the squirrels. It suggested splitting *Sciurus* into multiple new genera. This means many squirrels previously called *Sciurus* might belong to different groups now.

The 2020 study provided very specific new names for many squirrels. For example, it suggested the Persian squirrel should be *Sciurus anomalus*. It suggested the Japanese squirrel should be *Sciurus meridionalis*. It also looked at the Western gray squirrel, which it placed in *Hesperosciurus*. Some squirrels were moved into entirely new groups, like the genus *Neosciurus*. The study also looked at the Andean squirrel. It suggested moving this squirrel to a group called the dwarf squirrels. Specifically, it assigned the Andean squirrel to a new genus called *Leptosciurus*.

Some findings in the study helped clear up confusion about specific species. The researchers agreed with older assessments to synonymize Richmond's squirrel into the Red-tailed squirrel. They also reassigned the Red-tailed squirrel into a South American genus called *Syntheosciurus*. This genus is part of the Microsciurina group. Even with such advanced genetic tools, some questions remain. The 2020 paper did not include genetic sampling for every single squirrel. It did not have data for *gilvigularis*, *meridionalis*, *sanborni*, or *flammifer*. Scientists must continue to study these animals to reach a final understanding.

The study of *Sciurus* connects to the broader field of evolutionary biology. By looking at DNA, scientists can trace how animals changed over time. They can see how a single genus can split into many different branches. This helps us understand how life spreads across continents like South America and North America. Every time a scientist reclassifies a species, they are refining our map of nature. This work shows that our knowledge of the natural world is always growing and changing.