Cubs, Cubs, and more Cubs!
First year cubs, sometimes called "spring cubs" or "first summer cubs", were born the previous winter inside their mother's dens. These two cubs pictured above were photographed in July and are about six months old.
Bears are the only mammals to give birth while hibernating. Grizzly bear cubs only weigh about 21-25 ounces when they are born, and are about the size of a small chipmunk. Born in January or Febuary, cubs will nurse and grow inside the den for the next four or five months.
Grizzly bears can give birth to up to four cubs, although litters of two and three are most common. The number of cubs that are born depends on how healthy and fat a mother is at the time she enters the den. (For more information on this topic read about delayed implantation)
First year bear cubs are completely dependent on their mother and will stay with her through two or three summers. The first year of life is perhaps the toughest for grizzly bears - as many as 40% of grizzly cubs die before they turn one year old.
Bear cubs follow their mother everywhere she goes. Sticking close to mother helps protect cubs from predation by bears and wolves.
This grizzly cub is chasing after mom (not pictured) who is wading through a river to search for salmon.
While in the den, bear cubs subsist entirely on their mother's milk and perhaps a bit of her saliva. During their first summer bear cubs nurse frequently, and grizzly milk is about 30 % fat. (Read more about grizzly nursing)
During their first summer grizzly bear cubs augment their milk diet with all the hundreds of food sources enjoyed by their mother. By tasting food sources cubs begin to memorize where and when different foods can be procured. This cub above was munching on sedge grass which can be up to 25% protein in early summer.
Clams are one of the meat sources that grizzly cubs learn to enjoy at an early age. Clams are an important part of a coastal grizzly bear's diet during spring and summer, and often their only consistent meat source before the salmon arrives in mid to late summer. This grizzly mother (Patricia) was leaving behind scraps of clams for her cubs to dig up and find. Moving one hole behind their mother, the cubs gnawed off bits of meat still stuck to the clam shells and practiced the fine art of clam digging. Cubs learn about life by closely imitating their mothers.
First year grizzly cubs aren't big enough to start fishing for salmon on their own and often wind up watching their mother fish from the shoreline.
© 2008 Jessica Teel