56 Fat Marmot Week Facts from Colorado

What Fat Marmot Week Is

Fat Marmot Week is a public wildlife contest created by scientists at the Rocky Mountain Biological Laboratory in Gothic, Colorado.
The inaugural event runs from 24 to 29 August 2026.
People vote online in a tournament-style contest to choose a favourite well-fed marmot.
The format takes inspiration from Alaska's popular Fat Bear Week.
The contest celebrates weight gain because stored fat helps marmots survive months without eating.
Organisers also use the event to explain the science behind one of the world's longest-running mammal studies.
Fat Marmot Week was created in part to attract financial support for continuing that research.
The winner is due to be announced on Saturday, 29 August.

Stonehenge is a female whose litter was killed by a badger during a difficult 2026 season.
Researchers remember Stonehenge for repeatedly sounding alarm calls at passing cyclists.
Dan's Hat did not breed in 2026 and also lost nieces and nephews to a badger.
Open Kite is described by the research team as the marmot that dominates the laboratory townsite.
Citroen is Open Kite's mate and has helped care for her pups even though he is not their biological father.
Dawn has fathered multiple litters over the past five years and has also been observed tasting rocks.
Marmot 1 is a watchful mother that shares and modifies a burrow with another marmot named 2.
Goblin, also called G, is known for running between burrows while still gaining substantial summer weight.

Yellow-bellied marmots spend summer building the energy reserve they will use during hibernation.
An individual can grow to as much as three times its earlier body weight before winter.
The Colorado marmots hibernate for roughly five months when alpine food is scarce.
Fat is stored energy, so a chunky late-summer body can be a survival advantage rather than a sign of poor health.
Marmots eat grasses, flowers and other vegetation available around their colonies.
Wildflowers are an important seasonal food source in the Gothic study area.
Record-low snowpack in 2026 contributed to fewer wildflowers and made weight gain harder.
Earlier snowmelt also left marmots exposed to predators for a longer portion of the year.

Scientists at the Rocky Mountain Biological Laboratory have tracked yellow-bellied marmots since 1962.
Kenneth Armitage of the University of Kansas founded the study and led it for 41 years.
UCLA ecologist Daniel Blumstein took over leadership in 2001.
Blumstein now co-leads the project with Julien Martin of the University of Ottawa.
The project is described as the world's second-longest study of individually marked mammals.
Only Jane Goodall's long-term chimpanzee research began earlier among comparable individual-based mammal studies.
Researchers investigate marmot genetics, behaviour, communication, social lives and responses to climate change.
Following known individuals across decades reveals patterns that a one- or two-year wildlife project could miss.

Yellow-bellied marmots are the largest members of the squirrel family found in their Colorado habitat.
They can live alone, in small family groups or in colonies containing more than 20 animals.
That flexible social system differs from species that must live in a group to survive or raise young.
Alarm calls warn nearby marmots when a predator or unfamiliar disturbance is detected.
Badgers are important marmot predators and affected several contestant families in 2026.
The project has helped pioneer the use of social-network analysis in animal behaviour research.
Nearly 25 years of social-network records help scientists examine why some relationships persist while others change.
Around 100 study animals died over the winter before the first Fat Marmot Week, making 2026 especially difficult.

The Rocky Mountain Biological Laboratory was founded in 1928 near Crested Butte and hosts visiting field scientists.
Long studies help separate an unusual season from a lasting environmental trend.
Deep snow one winter and very little snow the next can lead to sharply different survival and breeding outcomes.
Climate change makes long-term records valuable because researchers can compare present behaviour with decades of earlier observations.
The marmot team has experimented with social media, fundraising videos and even a marmot-themed beer to support its work.
Fat Marmot Week gives the public a low-pressure route into subjects such as predation, hibernation and alpine ecology.
Fans should follow the animals through official project channels rather than approaching or feeding wild marmots.
The real prize behind the contest is a stronger public connection to the long-running research and the alpine ecosystem it documents.