Hayden Valley in Yellowstone National Park is one of the best places to have the opportunity to view grizzly bears. The experience is enhanced even further when visitors have the opportunity to view a bear feeding on a carcass.
Grizzlies are classified as omnivore generalists, meaning anything that may have some sort of nutritional value may be part of their diet (Robbins et al. 2004). Grizzly diet in Yellowstone consists of more than 260 plant and animal species, with plants making up nearly 70% of that number. Typically, contemporary adult females and sub-adult’s diets consist 60% of plants and 40% of meat, whereas contemporary male diets consist 80% of meat and 20% of plants (C.T. Robbins, 2006). Elk, trout and other meats that are consumed by grizzlies are approximately 90% digestible. To the contrary, plants and forbs such as dandelions and clover may only be approximately 40% digestible (Pritchard & Robbins, 1990). Being omnivore generalists, grizzlies seek to find and consume the most nutritious foods. Because of this, their diets do change, and shift overtime based on the abundance and availability of given food sources. Elk are an important food source to grizzly bears during in spring, early summer, and fall, even with numbers decreasing in certain areas of the park. In the Yellowstone Lake area, male grizzly bears feed on an adult elk carcass about every 4 days; females every 14 days. However, feeding on ungulates is very opportunistic, meaning grizzlies must feed on other food sources (Gunther and Renkin 1990, Barber-Meyer et al. 2008, Fortin et al. 2013)
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One of the more visible grizzly bears in Yellowstone National Park is GB815 and her 1 remaining yearling cub.
Last May 2016, she was observed with three cubs of the year (COY). This year, she was first observed this year on April 27, 2017, with only one surviving yearling, pictured below. Jort Vanderveen was fortunate enough to observe these two grizzlies near Norris, YNP this spring. Please visit Jort's Photography for more astounding images. 815 was first captured June 10, 2015 near Gibbon River in Yellowstone National Park. Her capture was for research purposes; the handling agency during her capture was the Interagency Grizzly Bear Study Team. GB815 is 10 years old as of 2017. I was fortunate enough to visit the den of GB815 and look at how she constructed her winter lair. A very, very difficult place to get into; she certainly was very well fortified and protected in this environment. Unfortunately, this den is partially collapsed, and most likely will not be used again. Grizzlies very rarely use the same den twice, and with the weathering and collapse present in this structure, it is safe to say that nobody will be using this den again. Like many, this den was at the base of a tree, using the root structure largely for structural support, and was positioned with the entrance facing north. For more on den information, please review my post from July 16, 2017 which is pinned to the top of this page, or my website www.yellowstonegrizzlyproject.weebly.com. Any questions or comments please feel free to drop a line. Video to come later. During hibernation, grizzly bears inside Yellowstone National Park (and the Greater Yellowstone Ecosystem) are tasked with finding suitable areas to construct their winter dens. Typically, grizzlies in Yellowstone dig their dens on 30-60 degree slopes with northern exposures between the range of 6500-10000 ft (Judd et al. 1986). Grizzlies typically will select den locations at the base of trees on northern face. The orientation of the den can insure that significant snowfall will insulate the den during extreme temperatures (Craighead and Craighead 1972). Den construction typically takes 3-7 days, where the bear may move up to, or more than one ton of dirt and debris material (referred to as a tailings pile)(Craighead and Craighead 1972).
The den constructed consists of several parts: the entrance, tunnel, and chamber. Grizzlies will typically bring bedding material into their dens, including but not limited to spruce and pine boughs; sometimes even duff. Den entrances are typically small and grizzlies "bearly" fit through them. This is to minimize heat loss during the winter; additionally, a smaller entrance will cover with snow quicker than a larger one. The den I explored today, belongs to male GB427. Males and females with cubs typically have the largest dens. The entrance of the den was just large enough for me to be able to fit my shoulders comfortable through. The chamber was so large , I could have curled up and taken a nap! Details on the death of the iconic and legendary "Scarface" (#211) of Yellowstone have been released. The information below is a statement released by Jim Halfpenny, Ph. D and Connie Jeffcoat. It answers many questions surrounding the untimely death of bear #211.
"We are in possession of case files about the death of Scarface, bear number 211, released through a Freedom of Information Act (FOIA) disclosure and mailed to us on June 8, 2017. The documents include some key information that should be shared with the Greater Yellowstone Community, especially bear lovers. Scarface was killed by a hunter returning in the dark with a headlamp lighting his way. The investigation confirmed that Scarface was apparently shot at about 10 feet from the trail on which the hunter was walking when the encounter occurred. US Fish and Wildlife Service, in collaboration with other agency agents, could not disprove the claim of a self defense shooting. On July 5, 2016 the US FWS declined prosecution. Information in the documents counters several rumors that have been prominent. The hunter was not employed in Gardiner and was not a resident of Gardiner or Montana. The hunter was not a Native American. The hunter was neither an employee of Montana Fish Wildlife and Parks nor any other agency. The hunter was not a young lad from Pennsylvania. While those of us who knew Scarface may doubt the gravity of the situation in the dark, the evidence does not allow us to question the immediacy of the situation and evaluate the demand for prompt action. In recognition of evidence supporting a self defense situation and what may have happened with a dark colored bear in the dark of the night only illuminated by a headlamp, we will not release the name of the hunter. It is significant that the hunter apparently was not carrying bear spray. Perhaps a $45 expenditure might have save the life of this iconic bear. Dear friend, for a quarter century you have delighted and enlightened us – thank you. Now travel softly through the berry patches of your next life." Jim Halfpenny, Connie Jeffcoat June 13, 2017" This is a string of traffic over 300+ cars strong. The result of having two grizzly families, one on each side of the road. For many, getting home from work was a nightmare; 399 on one side of the road, while 793 was on the other!
This is a crowd of 75-100 people near Pilgrim Creek. For some here, it's their first time seeing a grizzly bear; some children present will take this memory and remember it for the rest of their lives, as will their parents. In this crowd, there are photographers, who make their livelihood off of the ability to photograph the wildlife. In this crowd, rangers patrol to ensure the safety of those patrons...ultimately, in this crowd, there is the existence of voters...voters who hopefully will exercise their right to help protect and maintain our public lands, so these amazing areas may exist for generations to come.
During my last outing in the field in East Yellowstone this past week, I used a thermal camera to observe and document some bears during the dusk and night time hours. My thermal imaging device is good for 600 yards, and surprisingly, I was able to view bears near the roadway. Please note that the temperature scale is not reflective of inner body heat; the temp is reflective of surface temperature and is deceivingly lower for mammals that are fur bearing.
Enjoy! During 1983, Yellowstone National Park began to close areas of high density grizzly bear habitat for part or all of the period when bears are not denning, called Bear Management Areas. These closures were intended to eliminate human entry and disturbance, prevent human-bear conflict and habituation of bears to people and near prime food sources, providing places where bears can pursue natural behavioral patterns and social activities (Robbins et al. 2006).
Females with COY typically have increased security for their young during spring by selecting habitats, and least preferred vegetation at higher elevations, while other bears in cohorts are found at lower, more productive elevations (Blanchard et al. 1991). Females with cubs may be displaced due to sub ordinance of the female to other bears in a very similar proximity, or even the ignorance of vulnerability of her cubs to predation, stemming from lack of experience (Blanchard et al. 1991). With this being said, the significant use of the Lamar Valley by grizzlies is important to recognize. Preventing human-conflict and eliminating disturbance is a crucial element in assuring that these bears can behave and live normally, as bears should. I have attached an image of the proposed Lamar Valley bear management area. This area was constructed based on density of grizzly observations, estrus (courting activity) and presence of females with cubs. Please note this is a MODEL, a mere SUGGESTION and effort to alleviate, and prevent future human-bear conflict. Comments are welcomed.
http://nwsportsmanmag.com/headlines/feds-announce-north-cascades-grizzly-bear-restoration-alternatives/
Hello all! So far this year, my project has archived 1000+ images of grizzlies from all over Yellowstone National Park! All of these images are crucial in the positively identifying certain bears (mainly females with cubs). The last bear this year was observed on December 3rd from some distance, and at this time, we can speculate and say that grizzlies in Yellowstone have all entered hibernation. That being said, the work is just beginning.
Data analysis and the construction of the publication has begun this week and will continue over the next several months. So far my study identified 19 females with cubs in the year 2016 (10 females w/ COY, 6 females w/ yearlings, and 3 females w/ 2 year-olds). Anyone who has images, and who would like to contribute to the publication some sort of material, please contact me via email Brasingttj12@uww.edu. Your contributions, assistance, and following of this project are critically important in the long term management and conservation of grizzlies in the Yellowstone ecosystem and national park! Thank you! -Tyler |
AuthorTyler Brasington is a native born and raised Pennsylvanian, yet proud current Wisconsin resident. He graduated from the University of Wisconsin-Whitewater with a B.S. in Environmental Science. Currently, Tyler is pursuing his masters in Natural Resources with the University of Wisconsin-Stevens Point. He has worked in Yellowstone National Park under the guidance and supervision of Dr. George Clokey and Dr. Jim Halfpenny. Disclaimer: The information and views expressed on this page do not necessarily represent the views of the Department of Interior, US Geological Survey, National Park Service or the United States Government.
The Greater Yellowstone Grizzly Project
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February 2021
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