There are many different species of bears, from grizzly bears to polar bears to black bears. Many bears are considered endangered today due to development in their natural habitat and illegal hunting. Most female bears are ready to mate by the time they are 3 years old and typically mate until they reach about 8 years of age. Black bears mate in their fourth year, whereas grizzlies might wait until they are 7 years of age.
Bears tend to mate in the spring. Most bears mate from May to June, just after they emerge from hibernation. The females leave "scent trails" to attract males for mating. This can sometimes attract more than one male bear, which leads to fighting
For grizzlies, the males court the females by following them and making snorting sounds. This process may last several days. Female bears have learned to be wary of larger male bears and the male has to gain her trust. Once the courtship period ends, mating begins. Mating usually takes course over several days. Some females mate with different males over a period of several weeks. However, once mating is over, the female will not remain near the male and they go their separate ways. Bears live alone; the father never again sees the mother or the bear cubs.
Bear Gestation and Birth
Even though a female has a fertilized egg, this doesn't necessarily mean she will give birth. Although the egg is fertilized, the female must still forage and build up enough fat stores to see her through the winter. It is very difficult for an underweight female to give birth. Because of this, the egg is not implanted in the womb until the following fall after mating season. This is called delayed implantation.
The fertilized egg becomes a blastocyst. This is a tiny embryo. However, once the blastocyst is formed, the bear stops growing and floats in the uterus until hibernation season. If the female bear is in good condition, the embryo implants in the uterus and the baby bear will be born. If she is not in peak shape, then her body reabsorbs the embryo and she will not become pregnant.
The female bear has a gestation period of between 3 to 9 months, depending upon species of bear. Bears, who hibernate, typically give birth during that time and cubs nurse through the hibernation season. Most people think that bears sleep all winter, but the truth is that mother grizzly and black bears awaken in January or February to give birth.
Bear cubs are born in a litter. Litters typically range between 1 and 3 bear cubs. Bear cubs usually live with the mother bear for 2 or 3 years, until it is time for her to mate again.