Fowlea asperrimus
Silhouette: Alex Slavenko · PhyloPic
In 3 days ~90% in a week >90%
Boulenger's keelback (Fowlea asperrima), also known commonly as the Sri Lankan keelback, is a species of water snake in the family Colubridae. The species is endemic to Sri Lanka. The common name "Boulenger's keelback" is in honour of Belgian-born British herpetologist George Albert Boulenger.
F. asperrima is found in Sri Lanka, in both dry and wet climatic zones up to 1,000 m (3,300 ft) above mean sea level. It is abundant in waterways, such as flooded rice fields, ponds, lakes, marshes, rivers and streams. The body of F. asperrima is short and cylindrical, and has a clear neck and slightly pointed head. The eyes have rounded pupils, and the nostrils are narrow, directed slightly upwards. The tail is long. At hatching, it is 10 cm (3.9 in) long and grows to an adult length of 40–70 cm (16–28 in). The female is longer.
F. asperrima has one pair of internasals; the posterior parts are narrow. One loreal, preocular, postocular and three temporals are found. Of the 9 supralabials, 4 and 6 connect with the eye. Ventrals number 131–146, and the undivided subcaudals are 73–93 in count. At midbody there are 19 rows of dorsal... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Sinharaja Forest Reserve | 🇱🇰 Sri Lanka |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Colombo [Sri Jayawardenepura Kotte] | 🇱🇰 Sri Lanka |
Likely
About 50% of wildlife watchers report a Boulenger's Keelback sighting in Sinharaja Forest Reserve on a given day, based on 58 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 6th most-seen of the 32 reptiles we can rate there. Over three days the chance rises to about 90%, and over a week to over 90%, if each day is a fresh chance.
March and August
In those months about 70% of wildlife watchers report a Boulenger's Keelback in Sinharaja Forest Reserve on a given day, against about 30% in September, the lowest month.
Between 4 and 7 am
Across all the parks we cover, that three-hour window holds the most Boulenger's Keelback sightings with a recorded time, and about 7 in 10 of them come between 6 am and 6 pm: it is most active around dawn and dusk.
Only Sinharaja Forest Reserve, in our data
Sinharaja Forest Reserve is the only park on Wallace's Line with enough records to rate Boulenger's Keelback sightings: about 50% of wildlife watchers there report one on a given day.
Same family: Colubridae
The closest relatives of the Boulenger's Keelback that you can see in Sinharaja Forest Reserve (family Colubridae, Colubrid Snakes) are Green Vine Snake (about 80%), Stripe-Tailed Bronzeback (about 40%) and Ceylon Wolf Snake (about 40%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Boulenger's Keelback is recorded against all the reptiles logged in Sinharaja Forest Reserve (58 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.
