Spring fever is raising temperatures and melting the snow in Grand Teton National Park. The season is in full swing, as new life joins us in the Park. Herds are beginning their migration from lower winter feeding grounds to higher summer grounds and females are beginning to give birth, providing the opportunity to observe and study Mother Nature at her finest.
Below is a breakdown for understanding the process of life for some of our larger mammal populations in the Park:
As the male moose emits a deep, grunting call, his rutting season begins in September and extends into October. Bulls guard their right to mate through intimidation and fights. Around mid-May to early June, one or two calves are born to the cows and will remain close, weaned in winter or the following spring.
Showing dominance through bellowing, wallowing, and fighting, bull bison mate in late July and August. During rut, one bull will remain with one female until she is ready to mate. One calf will be born in late April and May and may be suckled through its second winter. Calves are able to keep up with the herd soon after birth.
The cool fall air from August to mid-October echoes with the bugling of mature bull elk, signaling their rut season. Bulls equipped with mature antlers, guard their opportunity to mate with their harem through aggressive intimidation and fights. One calf will be born the following spring from May to June, and weaned in 4-5 weeks.
Usually having several partners, the male grizzly (boar) will mate from May to early June. Mother Nature delays the implantation of the embryo to assure the female (sow) to reach the den and assure chances for a successful birth. Entering the den beginning in mid-October, normally, one to three cubs will be born between January and February, during hibernation. Female and cubs generally emerge from the den beginning in April. A mature female will usually breed every three years after chasing off the previous young, to protect them from attacks from the mating boar.
Usually having several partners, the male black bear (boar) will mate from May to early June. Mother Nature delays the implantation of the embryo to assure the females chances for a successful birth. Entering the den beginning in November, normally, one to three cubs will be born between January and February, during hibernation. Female and cubs generally emerge from the den beginning in March. The cubs normally winter with their mother and are weaned the following September. A mature female will usually breed in alternate years.
Each morning, I peer through the windows of the upper lobby of Jackson Lake Lodge to observe the expanse of nature surrounding us. Not far from where I stand, elk and moose cows are migrating to Willow Flats to give spring birth. What a fulfilling sight to experience Mother Nature’s wonder. As these populations assemble, so do others. We are beginning to observe the gathering of wolves and grizzly bears. Spring calves provide an ample food source for predators and this season will be no different. By visiting, you are experiencing part of the Greater Yellowstone Ecosystem, one of the largest intact temperate-zone ecosystems on Earth today. We invite you to come and witness this spectacle for yourself.
Seeking a great resource on information about the seasonal timeline of our Greater Yellowstone Ecosystem, which encompasses Grand Teton National Park? “For Everything There Is A Season,” by Dr. Frank C. Craighead, Jr., Ph.D., provides a wonderful outline of what a year entails here.
Posted from Don’s Corner ~ GTLC Interpretive Specialist