Pine Marten vs Fisher: What’s the Difference?

Pine martens and fishers are related mustelid animals. That’s why people often mistake pine martens for fishers or the other way around. However, if we look closer, we’ll notice the differences between them, including the most obvious ones – their size and appearance! 

What if we told you pine martens could be four times lighter than fishers? Or that fishers are some of the few porcupine predators? If you want to learn more incredible facts about the two that will help you tell them apart, keep on reading!

Comparing Pine Marten vs Fisher

The Key Differences Between Pine Martens and Fishers

We’ve already established some basic differences between pine martens and fishers. In this section, we’ll discuss some of them in detail to help you understand these two animals better.

You’ll discover how they differ from each other in size, appearance, diet, predators, threats, behavior, habitat, reproduction, and lifespan. If you’ve landed on this page knowing nothing about pine martens and fishers, you’ll become a master at distinguishing them once you finish reading!

Pine Marten vs Fisher: Size

Fishers are much larger and heavier than pine martens. 

Pine martens’ average body length is 16.5 – 20.5 inches, and their tails can measure 9 – 11 inches. In contrast, fishers have a body length that can reach 30 inches, and a 12 to 17-inch tail! This makes them approximately twice as big as pine martens! They’re also much heavier.

While pine martens’ average weight is 1 – 3 pounds, fishers can be as light as four pounds or as heavy as 13 pounds! The largest male fisher on record weighed 20 pounds – five times a pine marten’s weight!

Pine Marten vs Fisher: Appearance

A fisher’s fur is longer than a pine marten’s. Both animals’ fur changes depending on the season. One fisher peculiarity is that the fur depends on the animal’s sex, making males’ fur coarser than females’.

Pine martens have light to dark brown fur with a white-yellowish mark on their throats. Fishers are darker, sometimes even black. They’re gold or silver from the face to the shoulders and brown with white patches on the undersides. During summer, their coats have a lighter shade. 

Pine martens have semi-retractable claws, while fishers have retractable claws. Both animals have large legs. Fishers have an advantage, as their ankle joints are extremely mobile, allowing them to descend trees head-first. Both animals have small rounded ears, small dark eyes, and thin bodies. 

Pine Marten vs Fisher: Diet

Pine martens are officially classified as carnivores. They eat insects, small rabbits, voles, and birds. They are also known to feed on berries, nuts, and honey. 

Fishers are omnivores. They primarily feed on porcupines and snowshoe hares. In fact, they are one of the few porcupine predators. It takes them approximately 25 – 30 minutes to kill a porcupine. Poop evidence shows that they eat small birds and mammals, including deer. These small but ferocious mustelids are known to have killed and fed on bobcats, wild turkeys, and Canada lynxes. 

This indicates that their diet is more diverse than pine martens’ diet and that they have better hunting techniques. 

Pine Marten vs Fisher: Predators and Threats

Pine martens have more predators than fishers. They may fall prey to golden eagles, wolves, wildcats, and red foxes. In contrast, fishers are rarely hunted and killed by other animals. The only fishers that regularly fall prey are the ill or the old ones. Some of their predators are coyotes, bears, golden eagles, wolverines, and mountain lions. 

Pine martens’ population is also affected by human action. People often kill them because they attack barnyard animals. They also suffer from habitat loss, illegal shooting, and hunting for commercial reasons. In some areas, their fur is still prized.

Habitat loss and hunting are threats to fishers, too. Their fur started being prized in the 18th century and is still used for scarves and neckpieces. Their tails were once used for manufacturing spodiks – tall, black hats worn by Hasidic Jews in the 19th century. 

Many fishers live in captivity either for fur farming and scientific research or for “human entertainment” (at the zoo). They rarely come out during the day to meet the visitors. 

Pine Marten vs Fisher: Behavior and Habitat

Pine martens and fishers are solitary animals primarily active at night. They are both natural tree climbers and enjoy living in forests. Male pine martens and male fishers are aggressive towards other males in their territories. 

Fishers are known to leave scent trails so that males and females can find each other during the breeding season. Otherwise, they rarely meet or communicate with each other, just like pine martens. 

Pine martens mark their territories by leaving feces at the “borders” and are very aggressive if other males trespass their territorial boundaries.

Pine Marten vs Fisher: Reproduction

Pine martens reach their sexual maturity later than fishers – when they reach approximately 2 – 3 years old. They mate in July – August, and the fertilized egg reaches the uterus seven months later. The gestation period is one month. Their litter size is 1 – 5. 

Fishers’ mating occurs from late March to early April. The implantation happens ten months later, and the gestation period is 10 – 12 months. Fishers become sexually mature when they’re one year old. Their litter size is 1 – 6. Baby fishers are called kits.

Pine Marten vs Fisher: Lifespan

Not much is known about the lifespan of pine martens and fishers. Some records indicate an approximate average.

Records show that a pine marten individual lived 18 years in captivity, which is an extraordinary age, considering that their average lifespan in the wild is 3 – 4 years. On the other hand, the pine marten lifespan record in the wild is 11 years, which, again, creates a big discrepancy between the average 3 – 4 years. Hopefully, more studies will be conducted to bring evidence regarding the pine marten’s life expectancy.

Things get a bit clearer for fishers, as their average lifespan in the wild is 7 – 10 years. Some captive individuals lived up to 10 and 14 years, although specialists consider that fishers are prone to developing various diseases in captivity. 

Up Next:

• Pine Marten vs Mink: What’s the Difference?
• Pine Marten vs Least Weasel: What’s the Difference?

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