Pyrrharctia isabella
In 3 days ~20% in a week ~40%
Pyrrharctia isabella, the Isabella tiger moth, whose larval form is called the banded woolly bear, woolly bear, or woolly worm, occurs in the United States and throughout Canada. It was first formally named by James Edward Smith in 1797.
The thirteen-segment larvae are usually covered with brown hair in their mid-regions and black hair in their anterior and posterior areas. In direct sunlight, the brown hair looks bright reddish brown. The setae are uniform in length, unlike in other tiger moth larvae with similar appearance. Adults are generally dull yellowish through orangish and have robust, scaly thoraces; small heads; and bright reddish-orange forelegs. Wings have sparse black spotting. Each abdominal segment bears three black dots.
The Isabella tiger moth can be found in many cold and temperate regions. The banded woolly bear larva emerges from the egg in the fall and overwinters in its caterpillar form, by allowing most of its mass to freeze solid. First its heart stops beating, then its gut freezes, then its blood, followed by the rest of the body. It survives being frozen by producing a cryoprotectant in its tissues. This freezing occurs outside of body cells... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Elk Island National Park | 🇨🇦 Canada | |
| 2 | Shenandoah National Park | 🇺🇸 United States | |
| 3 | Redwood National Park | 🇺🇸 United States | |
| 4 | Cape Breton Highlands National Park | 🇨🇦 Canada | |
| 5 | Acadia National Park | 🇺🇸 United States | |
| 6 | Gros Morne National Park | 🇨🇦 Canada | |
| 7 | Great Smoky Mountains National Park | 🇺🇸 United States | |
| 8 | Yosemite National Park | 🇺🇸 United States | |
| 9 | Point Pelee National Park | 🇨🇦 Canada | |
| 10 | Pacific Rim National Park Reserve | 🇨🇦 Canada | |
| 11 | Yellowstone National Park | 🇺🇸 United States | |
| 12 | Great Bear Rainforest | 🇨🇦 Canada | |
| 13 | Riding Mountain National Park | 🇨🇦 Canada | |
| 14 | Olympic National Park | 🇺🇸 United States | |
| 15 | Merritt Island National Wildlife Refuge | 🇺🇸 United States | |
| 16 | Everglades National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Minneapolis [Saint Paul] | 🇺🇸 United States | |
| 2 | Portland | 🇺🇸 United States | |
| 3 | Montreal | 🇨🇦 Canada | |
| 4 | Boston | 🇺🇸 United States | |
| 5 | Seattle | 🇺🇸 United States | |
| 6 | Toronto | 🇨🇦 Canada | |
| 7 | Vancouver | 🇨🇦 Canada | |
| 8 | Detroit | 🇺🇸 United States | |
| 9 | Baltimore | 🇺🇸 United States | |
| 10 | Washington | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report an Isabella Tiger Moth sighting in Denver on a given day, based on 61 verified sightings from GBIF citizen-science data. It is the 99th most-seen of the 461 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
February, April, August–October and December
In those months about 10% of wildlife watchers report an Isabella Tiger Moth in Denver on a given day, against under 5% in January, March, May–July and November, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Isabella Tiger Moth sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
13th of 18
Of the 18 cities where we can rate Isabella Tiger Moth sightings, Denver ranks 13th at about 10%. The best odds are in Minneapolis [Saint Paul] (United States, about 20%), Portland (United States, about 20%) and Montreal (Canada, about 20%).
GBIF citizen-science records
It is estimated from how often the Isabella Tiger Moth is recorded against all the insects logged in Denver (61 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
