National Park Service · Denali National Park & Preserve
An interactive exploration of wolf population data, research, and resources for Denali National Park & Preserve, 1986 - 2025.
01 › Background
Denali's wolves have been studied since Adolph Murie's groundbreaking fieldwork in 1939. The modern radio-collaring program launched in 1986 after park employees discovered poached wolf carcasses in 1985, sparking a decades-long commitment to understanding and protecting these packs.
As a keystone predator in interior Alaska, wolves regulate moose, caribou, and Dall's sheep populations, which in turn shape vegetation patterns across the entire landscape. Tracking wolves effectively tracks the health of an entire ecosystem.
Biologists maintain one or two radio-collared wolves per known pack. Collared wolves are located approximately twice per month, with intensive counts in September - October for fall pack sizes and pup survival, and again in March for late-winter pack sizes (post-winter dispersal).
From 1986 - 2013, roughly 25% of collared wolf deaths were caused by humans, mostly through legal kills when wolves ventured beyond park boundaries. About a third were killed by rival packs, with the rest from natural causes including starvation, drowning, and disease.
The population is a constantly shifting mosaic of pack territories. Packs form, split, merge, migrate, and vanish. More than 400 wolves have been collared since 1986, revealing complex social dynamics, long-distance dispersals, and intriguing adoptions of unrelated wolves.
02 › Population Trends
Spring counts represent late-winter survival; fall counts capture the annual boom after pup season. The gap between them reveals reproductive successes and mortality rates.
03 › Pack Dynamics
Mean pack size fluctuates with prey availability, pup survival, and territorial conflicts. Fall packs are almost always larger than spring; the difference represents the year's pup cohort.
04 › Territorial Range
Spring counts, taken in March before the summer pup season, represent late-winter survival and are considered the more reliable baseline for tracking the population through time. As GPS collar technology improved through the 2000s, territory boundaries became more precisely defined, making the monitored area increasingly consistent in recent years.
05 › At a Glance
Each cell is one metric for one year. Hover for exact numbers.
06 › Key Moments
Adolph Murie conducted the first major scientific study of wolves at what was then Mount McKinley National Park, producing The Wolves of Mount McKinley - one of the earliest landmark publications in wolf ecology.
Park staff found the skinned remains of seven wolves in remote areas of Denali. The discovery revealed the extent of illegal aerial poaching and catalyzed the decision to launch intensive radio-collar monitoring.
Researchers L. David Mech and Layne Adams initiated a comprehensive wolf-collaring project, starting with just 3 packs and 22 wolves counted that spring. The program has continued uninterrupted for nearly four decades.
The population surged to 142 wolves counted in fall 1991, with exceptional pack sizes across the study period. Favorable prey conditions and high pup survival drove the boom.
In fall 2007, wolf population hit its historical peak since monitoring began at 147 wolves counted across 20 packs. Twenty packs were being tracked simultaneously, the most in the program's history.
Wolf density dropped to historic lows despite similar monitoring effort. Low snowfall had reduced prey vulnerability, and several packs fragmented or disappeared. GPS technology simultaneously expanded estimated territory areas.
Tourism collapse during the pandemic put the monitoring program's funding at risk. The National Park Foundation stepped in to ensure the world's longest-running interior Alaska wolf study continued without interruption.
Both 2024 spring and fall counts came in at 56 wolves across 10 - 11 packs, a notable decline from the 2021 - 2022 rebound. Spring 2025 counts continued the downward trend with 46 wolves across 11 packs but surged upward in the spring with 54 wolves across 9 packs.
07 › Methodology
A combination of decades-old field techniques and modern satellite technology keeps this program running across millions of acres of wilderness.
After fresh snowfall, researchers track wolf packs by air and dart one or two members, typically the breeding pair, from a helicopter. Wolves are weighed, measured, blood-sampled, and fitted with VHF or GPS collars.
Collared wolves are located approximately twice monthly via radio telemetry. Intensive counts occur in September - October (fall pack sizes and pup counts) and March (late-winter pack sizes), producing the spring and fall numbers in this dataset.
A full year of telemetry locations (April - March) defines each pack's territory. The combined monitored area adjusts each year to reflect only the area with reliable coverage. GPS collars have made these boundaries increasingly precise in recent years, avoiding the need to make assumptions about "fractional packs" at the edges. Density, calculated as wolves per 1,000 km², becomes directly comparable year to year. Applying this density to the ~17,270 km² of viable wolf habitat north of the Alaska Range yields a park-wide population estimate, though exactly what constitutes "viable habitat" varies somewhat across publications.
08 › Get Involved
The field research presented here represents decades of dedicated biologists working in extreme conditions. You can contribute to wolf conservation in Denali.
If you visit Denali and observe wolves, your sighting report contributes valuable data to ongoing research efforts. The National Park Service maintains a wolf sighting index that helps track real-time pack activity and visitor engagement with the landscape.
View the Wolf Sighting Index →The wolf monitoring program depends on sustained funding for field operations, helicopter surveys, and collar maintenance. Consider supporting the National Park Foundation or donating directly to Denali's conservation initiatives to ensure this critical research continues.
Learn about the National Park Foundation →Alaska Wildlife Alliance (AWA) advocates for a protective habitat buffer zone adjacent to Denali to shield wolves from hunting and trapping. Between 2000 - 2010, the buffer increased both wolf viewing opportunities and visitor experiences. Support efforts to reinstate this critical protection.
Explore AWA's Wolf Buffer Campaign →