The breeding cycle for this species begins in April and extends into July with babies being born days later. To the casual observer it would look like the babies are born in August when they are first visible above ground when they were really born in July. The California chipmunk , found in the mountains of southern California, offers more complexity to the baby making equation. The California chipmunk only has one breeding season but it is incredibly long lasting from January through July.
Such a long breeding season results in an equally long season of births. To make things more interesting, a single female California chipmunk can breed TWICE in the same season producing two litters of babies. So, for the California chipmunk, babies can be born anytime between February and August. The Sonoma chipmunk , found in northwest California, is an interesting example of another variable in the chipmunk baby equation.
This species has a single spring breeding cycle. The reason for the elevation dependent mating timing is unknown. The gestation period for these chipmunks lasts for 31 days and they give birth to 3 to 5 infants. The Red-tailed chipmunk , found in the central Rocky Mountains, adds another piece to the baby puzzle. In April, mature male chipmunks are ready to mate two weeks before females and sometimes compete with each other for females.
Males often travel long distances to check out female territories to make sure they are ready to mate. Some males mate with several females. Species like the eastern chipmunk and Siberian chipmunk go through two different breeding periods, in early spring and then again in late summer.
Chipmunks communicate to members of the opposite sex by vocalizing chirps, croaks and other verbal signals. Chipmunks develop in their mother's womb for at least a month. Litter sizes vary. For example, least chipmunks have a litter with two to six young, while Siberian chipmunks have three to eight young. Newborn chipmunks are born hairless and don't open their eyes for the first month of life. In species such as the eastern chipmunk, females provide all of the care to their litters.
This scolding noise is often made by a chipmunk watching an intruder from a safe vantage point. Some scientists think that it may also be the mating call of the female chipmunk. Surprisingly, in animals so quick to befriend curious children and captivate their jaded elders, chipmunks are solitary animals. Most chipmunks construct tunnels and chambers in the ground that have entrances that are well hidden under rocks or tangled bushes.
Less typical are those western species that spend a fair amount of their time in trees and sometimes even nest in tree cavities. Each chipmunk has its own burrow and ignores its fellows except when conflicts arise or during mating or when females care for their young.
The chipmunk's home is an underground burrow. The burrow provides protection from the cold and also from the heat on hot summer days. It provides protection from enemies and it is also used to store nuts for the winter. The chipmunk starts the burrow by digging a hole about 25 to 70 cm deep. The chipmunk then digs a chamber room about 15 cm high and about 30 cm in diameter. The bottom of the chamber is lined with shredded materials like leaves and grasses.
This main area is used for hibernating, resting, giving birth and also food storage. Additional rooms are sometimes built to store food. When digging a tunnel, the chipmunk uses its teeth to cut roots from trees and shrubs. It uses its front and rear feet to push the dirt behind its body.
It then turns around and pushes the dirt out, using its head and nose like a bulldozer. The first tunnel is called a working tunnel because it is not the main entrance. The chipmunk doesn't want its main entrance to be surrounded by dirt and debris. This would make it easy for its enemies to find its home. In order to keep the main entrance free of dirt, the chipmunk builds a tunnel from the inside of the chamber. This tunnel goes to the surface of the ground. This main entrance may be seven or eight metres from the entrance to the working tunnel.
It is important to understand that each chipmunk's home is special. Some may have two or three chambers instead of just one. Some may have many tunnels leading up to the ground level.
The chipmunk also spends time changing its burrow. It may change the main entrance from time to time and also build additional chambers for the storage of food. The chipmunk usually has only one main entrance to its home. If it builds a new entrance, the old one is blocked with dirt. The chipmunk has also been known to block the main entrance at night before going to sleep. In the morning it simply removes the dirt and goes to work gathering nuts. A chipmunk spends much of its day collecting and storing seeds, which are its most important source of food.
Although most species of chipmunks most often forage on the ground, they all easily climb trees and shrubs to harvest nuts and fruit. When preparing food for storage, the chipmunk holds fruit and seeds in its dexterous front paws, and with specialized incisors, which are especially long and directed forward, it removes seeds from pods.
Then it uses its tongue to shift them backwards and stuff them between its teeth and the extensible skin in the cheek area, where they are held while the animal collects more food. The capacity of these cheek pouches increases with maturity. When the cheek pouches become full, the chipmunk deposits the seeds in its nest or buries them in shallow holes that it digs in the ground and then covers with earth, leaves, and other litter. In spring, chipmunks diligently search the ground for any seeds that remain from the previous summer.
As these are usually scarce, the small rodents eat young leaves and shoots until new fruit and seeds become available. Throughout the spring, summer, and autumn, the chipmunk's diet is supplemented with insects, earthworms, flowers, berries, cherry and plum pits, mushrooms, and occasionally eggs or carrion.
Rare instances of chipmunks preying on birds or small mammals have been observed. Chipmunks are active during the day and sleep in their underground burrows at night. The chipmunk is an alert, fast-moving animal. It spends much of its time hunting for food. The food is gathered in cheek pouches. These cheek pouches are like little shopping bags and are used to carry food to the underground burrow. In researching the chipmunk, scientists have found that it can carry over 50 watermelon seeds in these pouches.
The chipmunks eat a wide variety of foods, including acorns, chestnuts, hickory nuts, mushrooms, insects, fruit, and berries. Chipmunks feel most at home in areas with plenty of ground cover, including logs, trees, stumps, shrubs and rocks. Chipmunks dig extensive burrow systems directly underneath or next to natural or manmade cover.
They dig two types of burrows: shallow burrows in which they seek refuge while foraging during the day, and deeper, more complex burrows where they nest, store food and spend most of the winter months. Chipmunks are omnivores, dining on various types of foods that are found mostly on the ground.
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