Humboldt Marten USFS FPWC.tif 

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SAVING THE Humboldt marten

A stealthy, cat-sized forest carnivore in the weasel family, the Humboldt marten is so rare that it was thought extinct until rediscovered in 1996. Now, due to extensive logging of coastal old-growth forests in Northern California and Oregon — the only places it’s found — the marten has been eliminated from 95 percent of its historic range. Other threats to the marten abound, including wildfires and loss of genetic diversity due to population separation and a tiny overall population size. Fewer than 100 of these beautiful mammals are known to survive.

To make sure the Humboldt marten never slips out of human awareness again, in September 2010 the Center filed a scientific petition to protect the species under the federal Endangered Species Act. Although the U.S. Forest Service subsequently said protection may be warranted, the agency missed the deadline to make its next listing decision, so the Center filed a notice of intent to sue in April 2012.

Saving the marten means protecting its habitat and reestablishing population connectivity. Martens are secretive hunters that only move through dense shrub cover or areas with closed forest canopy, so extensive clearcutting has dramatically fragmented their range, isolating populations in Oregon and California.


HUMBOLDT MARTEN } Martes americana humboldtensis
FAMILY: Mustelidae

DESCRIPTION: Martens have medium-length glossy fur that ranges from tan to chocolate in color, with a lighter-colored throat patch and underfur and darkly furred legs and tail. The Humboldt marten in coastal northwestern California are on the smaller end of the American marten size range, with an average weight of 889 grams for males and 598 grams for females. These martens are slender, 1.5 to 2 feet long, and have large triangular ears and a long tail.

HABITAT: Humboldt martens are very strongly associated with closed-canopy, old-growth forests with complex structure on or near the ground. Martens are known to avoid younger forests and open areas such as clearcuts, as well as fragmented areas. They will not cross large areas with low canopy closure. Martens also require old-growth elements for denning sites. Kits are weaned at 42 days, emerging from their dens at 50 days to begin foraging independently.

RANGE: In California, the Humboldt marten historically occurred in coastal forests from Sonoma County, California north to the border of Curry County, Oregon. The marten also once occurred throughout coastal Oregon forests. Today, the subspecies has been extirpated from 95 percent of its California range and exists only in west-central and extreme southwestern Oregon.

MIGRATION: This species is nonmigratory.

BREEDING: Martens mate from late June to early August, with most mating occurring in July; they give birth in March and April.
LIFE CYCLE: Martens can live up to 14.5 years in the wild.

FEEDING HABITS: Humboldt martens primarily eat small mammals such as squirrels and voles, but they also eat huckleberries, salal berries, birds, eggs, reptiles, fish, carrion and insects. Diet is both regionally and seasonally variable.

THREATS: The primary threat to the Humboldt marten is logging of old-growth and coniferous forests, which eliminates, degrades and fragments its remaining habitat. The animal is also at risk from small population size and low genetic variability, wildfire, predation, climate change and legal trapping in Oregon.

POPULATION TREND: This subspecies has undergone drastic decline. In California, it appears to have declined by more than 40 percent from 2000 to 2008. In Oregon, the marten has been lost through


Humboldt Marten USFS FPWC.tif

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