Arctic Woolly Bear Moth: It Takes Them 7 – 14 Years to Mature

The Arctic is too cold for any moth to survive. However, the Arctic woolly bear moth is the only exception. Moreover, this insect spends 7 to even 14 years to fully become an adult. So, how can they triumph over the frozen depths of the North? And what takes them so long to emerge from the cocoon? Join us with the remarkable facts about the Arctic moth to know more!

Arctic Woolly Bear Moth
Scientific name: Gynaephora groenlandica
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Family: Erebidae
Genus: Gynaephora

1. They’re the only moth living in the Arctic

The Arctic woolly bear moth, a modest and remarkable member of the Erebidae family, inhabits solely the northernmost reaches of the Arctic region. Its habitat extends across the Canadian mainland, the northern islands of Canada, and the pristine High Arctic tundra of Greenland. This species is one of the amazing Arctic animals you can find.

2. Over 90% of their life is for hibernation

The life cycle of the Arctic woolly bear moth is truly exceptional and captivating. Once the eggs hatch, the tiny first-instar larvae engage in feeding activities. Their diet primarily includes arctic willow leaves, purple saxifrage, and arctic avens. Interestingly, they dedicate only 5% of their larval phase to eating, specifically during June. They spend the rest of their time freezing and staying in a dormant state.

The Arctic woolly bear moth caterpillar’s body is covered with soft hair and tan-brown color. It has an average size.

In July, as temperatures decrease, these larvae undergo preparations for hibernation by constructing a protective structure made of silk known as a hibernaculum. During this period, called diapause, they remain dormant until the next year when the snow begins melting. Upon awakening, they continue to eat, undergo molting into the second instar, and build another hibernaculum for the upcoming diapause. This cycle persists until they reach the 8th year.

To expedite their recovery, these larvae usually stay on rocks rather than vegetation, as rocks tend to thaw at a faster rate.

The arctic woolly bear moth stands out from other butterflies and moths due to its exceptionally long life cycle. Unlike most insects that undergo metamorphosis relatively quickly, the woolly bear caterpillar takes anywhere from 7 to 14 years to complete its transformation into an adult moth.

However, the Arctic woolly bear moth’s extended life cycle is not unique in the insect world. Take, for instance, the remarkable life cycle of dragonflies. These species spend a remarkable span of up to 5 years as aquatic larvae before they emerge and become an adult. On the other hand, certain cicada species display an even more astonishing endurance by remaining in the larval stage for 13 or 17 years.

3. Arctic woolly bear moth Adaptions

To survive in one of the coldest places in the world, Arctic woolly bear moth caterpillars have some marvelous adaptions.

Basking: A considerable amount of their active time is devoted to basking in the sunlight, enabling them to attain the ideal temperature for feeding and growth. Generally, they do this around midday, taking advantage of temperatures as high as 30°C, which exceed the ambient air temperature. Once they have fed, they bask once more before transitioning to a different area.

Moreover, basking permits the Arctic moth caterpillars to retain warmth through their hairs. This extends their period of activity and promotes efficient metabolic processes, including digestion.

An Arctic woolly bear moth caterpillar is basking

Staying in the rocks:

In their hibernation period, caterpillars opt for rocky areas to stay in their hibernaculum. The presence of cold rocks in their surroundings provides them with more consistent temperatures compared to the fluctuating conditions of the surrounding soil. This choice helps minimize the potential damage resulting from freezing and thawing cycles. Additionally, during springtime, rocks are more efficient at absorbing heat than vegetation, which facilitates the melting of snow and encourages the caterpillars to emerge earlier.

Arctic woolly bear moth is eating

The production of glycerol:

When the temperature drops to nearly freezing, Arctic woolly bear moth caterpillars break down their mitochondria and synthesize glycerol. They undergo a dormant state by removing their mitochondria, which hinders their ability to metabolize effectively. Glycerol serves as a protective measure, preventing their cells from freezing in harsh conditions.

4. The adult Arctic moth lifespan is short

When the caterpillars reach full maturity, they initiate pupation at the beginning of summer by constructing a dual-layered silk cocoon. This cocoon creates a hibernaculum, containing a pocket of air between the layers. It is worth noting that the mortality rate during this stage amounts to 13%.

Within a week, the adult Arctic moths complete their development and emerge. These moths exhibit sexual dimorphism, wherein males typically fly while females do not. Their bodies are pale gray, accompanied by pale gray forewings that reveal black-and-white streaks when spread open. They possess transparent pale gray hindwings. These Arctic woolly bear moths are most active throughout the summer.

They pupa and turns into adults in just a few weeks

They undergo a life cycle that spans just 2 weeks, including mating and laying eggs either on the ground or on nearby vegetation. This marks the beginning of a new cycle as the larvae emerge from the eggs. The hatching typically takes place in late June of the first year, while the mating and subsequent death occur in mid-June of the eighth or fifteenth year.

Similar to other flying insects, adult Arctic woolly bear moths don’t have mouthparts, rendering them unable to feed. Consequently, they do not partake in flower pollination or nectar consumption.

Arctic woolly bear moth adults

Surviving in the harsh Arctic environment poses considerable challenges for the moths, as it faces the cold and the constant threat of predators and parasitoids such as parasitic ichneumon wasps and flies.



Animal Facts 276

We are passionate animal enthusiasts with over a decade of experience studying animals. With a degree in zoology and conservation biology, we've contributed to various research and conservation projects. We're excited to bring you engaging content that highlights the wonders of the animal kingdom. We aim to inspire others to appreciate and protect wildlife through informative content grounded in expertise and passion. Join us as we delve into the captivating world of animals and discover the incredible stories they have to tell.

Leave a Comment