*Squirrels belong to the order "Rodentia", with 1650 species. It is the largest group of living mammals. It also comprises forty percent of all present day mammal species. There are over 365 species of squirrels in seven families. They include the tree squirrel, ground squirrel, and flying squirrel, as well as many squirrel-like mammals such as the gopher, ground hog and prairie dog.
*Squirrels are the most active in late winter, when the mating season begins. The males will chase females, as well as competing suitors. This ritual of chasing occurs through the trees at top speed while they perform some of the most breathtaking acrobatics imaginable. The period of gestation varies from 33 days in the smaller species of pine squirrels, up to 60 days for the larger species such as the common gray and fox squirrels.
*Squirrels are usually born in the early Spring. The average litter consists of four baby squirrels. This varies with climate and location. A second litter can occur in mid-summer if there is an adequate food supply.
* In the summer, squirrels are most active two to three hours after sunrise, resting in the afternoon and resuming activity again two hours before sunset. The squirrel will retire to its nest well before dark,and will rarely leave the nest in the dark. In the winter, the squirrel will complete its activities between dawn and mid-day, and will remain in or around the nest until the next day. During winter storms or severe cold, the squirrel may not leave the nest for days. The tree squirrel does not hibernate!
* Gray squirrels come in many colors. Shades of gray are the most common followed by shades of brown. There are also pure white and pure black squirrels, but both are variations of the gray squirrel. The common Red squirrel can have an all black coat. While the Kaibab squirrel has a black body with a white tail. Both are found in coniferous forests.
* The gray squirrel's diet consists of nuts, seeds and fruit. It will eat bird eggs, bugs, and even an animal carcass if there is no other food source available. The gray squirrel requires some salt in its diet, and may find this salt in the soil along roads where snow and ice may have been. The average adult squirrel needs to eat about a pound of food a week to maintain an active life.
* Squirrels communicate through a series of chirps. The frequency and the duration of the notes communicate everything from laughter to alarm. Their frequency range is normally between .01 KHz. and 10 KHz. (kilohertz). These sounds, when used in conjunction with tail gestures, form the basis for squirrel communication.
* A squirrel's teeth grow continuously. Their incisors will grow six inches per year, but stay short due to the constant wear they receive. The most common type of squirrel bite is a result of feeding a squirrel by hand. Never hold the food between your fingers, chances are very good you will be bitten. A squirrel's eyes are always looking for predators and they rarely focus on what they are eating.
* Squirrels have major and minor food preferences. Favorite foods include fruits, nuts and seeds. Peanuts and peanut butter are popular favorites. Walnuts and apples are good treats since they may naturally occur in the squirrel's diet. Tree squirrel diets vary by species and are determined by their habitat and season of the year.
* The largest animals in the squirrel family are the woodchucks (also called ground hogs or marmots) and have been known to dig beneath houses and other buildings. They also burrow into levees and dikes, causing damaging washouts. As housing developments have popped up in former farm land, woodchuck problems have become more common for home owners.