Sorex cinereus
Silhouette: Becky Barnes · PhyloPic
In 3 days ~10% in a week ~20%
The cinereus shrew or masked shrew (Sorex cinereus) is a small shrew found in Alaska, Canada, and the northern United States. This is the most widely distributed shrew in North America, where it is also known as the common shrew.
It is grey-brown in colour with a light grey underside and a pointed snout. It has a long tail that is brown on top and pale underneath with a dark tip. Its body is about 9 cm (3.5 in) in length including a 4 cm (1.6 in) long tail. It weighs about 5 g (0.18 oz). It has darker colouring than other shrews. Masked shrews can live up to two years, but, on average, only survive eighteen months.
In a long-term study done in Alaska, Yom-Tov and colleagues (2005) found that the masked shrew's body size contradicts Bergmann's rule. The study, done on 650 specimens and spanning from 1950 to 2003, examined body size in relation to ambient temperature. Measurements of body weight and the length of the tail, ear, hind foot, and body were taken. Results yielded that the masked shrew's body size decreased with high latitudes and with lower mean January temperatures, a trend that opposed Bergmann's Rule. It was suggested that this may be a coping mechanism... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Gros Morne National Park | 🇨🇦 Canada |
More parks will be added in future updates.
Rare
Under 5% of wildlife watchers report a Masked Shrew sighting in Vancouver on a given day, based on 5 verified sightings from GBIF citizen-science data. It is the 27th most-seen of the 28 mammals 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.
Any time of year
In every month with enough records, under 5% of wildlife watchers report a Masked Shrew in Vancouver on a given day, so our monthly data shows no clear season.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Masked Shrew sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 3 cities where we can rate Masked Shrew sightings, Vancouver ranks 3rd at under 5%, level with the leaders once rounded. The best odds are in Edmonton (Canada, under 5%) and Chicago (United States, under 5%).
GBIF citizen-science records
It is estimated from how often the Masked Shrew is recorded against all the mammals logged in Vancouver (5 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.
