Calosoma scrutator
In 3 days ~10% in a week ~20%
Calosoma scrutator, commonly known as the fiery searcher and caterpillar hunter, is a species of ground beetle belonging to the genus Calosoma. This beetle can be as large as 35 millimetres (1.4 in) long, and is hence among the largest of the ground beetles found in North America. The distribution of this species is relatively widespread, and is common in North America. The adult beetle is known to excrete a foul-smelling oil when it is handled. The oil has been described as smelling similar to rotten milk or rancid olive oil.
It was originally described in Virginia by Johan Christian Fabricius in 1775. It is a predatory beetle and also happens to be predatorial in its larval stage as well. Their varying colors and metallic shine make them very intriguing to those who spend time collecting different types of bugs. They are found mostly in North America along the east coast but have been found in Mexico, Venezuela, and Guatemala. Adults eat caterpillars and other worms, but most notably the forest tent caterpillar (Mala-cosoma disstria) and cankerworms. This fact gives Calosoma scrutator the nickname of "Caterpillar Hunter". These beetles are very good predators of agricultural pests such as spongy moth larvae. Predators that like to snack on the fiery searcher beetle include skunks, birds, raccoons, foxes, and toads. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Zion National Park | 🇺🇸 United States | |
| 2 | Grand Canyon National Park | 🇺🇸 United States | |
| 3 | Shenandoah National Park | 🇺🇸 United States | |
| 4 | Saguaro National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Austin | 🇺🇸 United States | |
| 2 | Dallas | 🇺🇸 United States | |
| 3 | San Antonio | 🇺🇸 United States | |
| 4 | Houston | 🇺🇸 United States | |
| 5 | Baltimore | 🇺🇸 United States | |
| 6 | Washington | 🇺🇸 United States | |
| 7 | New York City | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Fiery Searcher sighting in Saguaro National Park on a given day, based on 5 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 300th most-seen of the 354 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
April and September
In those months about 10% of wildlife watchers report a Fiery Searcher in Saguaro National Park on a given day, against under 5% in May–August and October–March, the lowest months.
Between 2 and 5 pm
Across all the parks we cover, that three-hour window holds the most Fiery Searcher sightings with a recorded time, and about 6 in 10 of them come between 6 am and 6 pm: it is seen both by day and at night.
4th of 4
Of the 4 parks where we can rate Fiery Searcher sightings, Saguaro National Park ranks 4th at under 5%. The best odds are in Zion National Park (United States, about 10%), Grand Canyon National Park (United States, about 10%) and Shenandoah National Park (United States, under 5%).
GBIF citizen-science records
It is estimated from how often the Fiery Searcher is recorded against all the insects logged in Saguaro National Park (5 verified sightings from 2019 to 2026), 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.
