Grizzly bear cubs 3600 990x742

The Life Cycle of Grizzly Bears

  • Mating

    The female grizzly bear will mate with several males if enough are in the area she inhabits.
  • End of Mating Season

    End of Mating Season
    For most grizzly bears, mating season runs from May into the first part of June.
  • Pregnancy

    The bear gestation period varies between 180 and 266 days.
  • Fattening Up for Hybernation

    Fattening Up for Hybernation
    The embryo's development goes on hold temporarily at first, as the female gorges herself on whatever foods are available during the summer and autumn to develop a layer of fat off to live on through the winter months.
  • Finding a Den

    Finding a Den
    The female chooses the site of her den, often under a log, in a cave or in a hollow tree.
  • Somewhat Hybernation

    Somewhat Hybernation
    She will then proceed to enter a sort of stupor that is not a true hibernation, with her body temperature, heart rate and breathing all reduced.
  • Growth of the Embryo

    Growth of the Embryo
    Once she is in this state, the embryo starts to develop once more, with the female giving birth to one to four cubs no later than March.
  • Giving Birth to Cubs

    Giving Birth to Cubs
    The newborn cub lacks fur and cannot see until it's a few days old.
  • Protection

    The cubs will continue to stay with their mother for as long as three years. The cubs need her protection from predators such as other bears, cougars and wolves.
  • Climbing

    The grizzly cub has the ability to climb trees with ease until it is about a year old.
  • Females Mate Every 3-4 Years

    Females Mate Every 3-4 Years
    Most females will breed once every three to four years, as it requires a few years to integrate their cubs into the world.
  • Young Adults

    Young Adults
    Once the cubs are capable of fending for themselves, the mother will drive them away from her and look to breed again. By this time the young grizzly weighs between 350 to 700 lbs. depending on the abundance of food.
  • Growing

    As these bears grow in size and strength, their diet will expand as they start to possess the ability to kill larger prey. These male grizzlies will wait until they reach their sexual maturity before they breed, with some mature at 4 years old and others needing as much as 18 more months to reach full adulthood.
  • Territories

    Grizzly bears will establish their own territories as they age.
  • Cycle Begins Again

    Cycle Begins Again