Russian Brown Bears

[brotherbear]

Quote: Bear Breeding: The baby bears are born in January when the mothers are dozing inside their snug dens. Females breeding for the first time often deliver only a single cub, but their subsequent litters usually include two, and there may even be three, rarely four, and exceptionally five. However, most she-bears give birth only every other year, although their fertility depends somewhat on the abundance of food. Up to a third of them may breed only once every three years.

The cubs are blind at first and at a weight of only 500-700 g ( 18-25 oz ) are very small in comparison to their mother's great bulk of around 150 kg ( 330 lb ): weight for weight, they are less than one-tenth the size of a human baby. This has survival value because the tiny creatures do not tax their mother's energy resources at a time when she must rely entirely on her body fat. But once they come out into the open, the cubs' initial chances of survival are not high. During the first year, 65% of them die, and 57% of those that live to experience their first birthday succumb before their second.

However, the fortunate cubs stay with their mother at first, sometimes for two summers, sleeping with her in her den during the winter along with their younger brothers and sisters. If the female breeds every year, she may have three generations of cubs in tow, with the eldest looking after the youngest ones - in Russian, they are called pestuny, which means 'nurses'.

Inevitably, when the offspring become sexually mature, the mother chases them away, and the females accept males during the midsummer rutting period. Whereas female bears reach their full stature when they are five years old, the males continue to grow until they are ten. Once adult, Brown Bears have few enemies except man, with a natural mortality rate of only 5% ( although the mortality rates are obviously higher in areas where the bears are hunted ). This means that some may enjoy the prospect of a long life of up to 47 years, although 30 is a more likely maximum. Reply