Opisthotropis andersonii
In 3 days ~20% in a week ~40%
Anderson's stream snake (Opisthotropis andersonii), also known commonly as Anderson's mountain keelback, is a species of snake in the family Colubridae. The species is native to Asia The specific name, andersonii, is in honor of Scottish herpetologist John Anderson.
O. andersonii is found in Hong Kong and Vietnam. The preferred natural habitats of O. andersonii are forest and freshwater wetlands, at altitudes of 300–900 m (980–2,950 ft). Dorsally, O. andersonii is blackish olive. Ventrally it is whitish, except for the chin and lower labials which are brown. The snout is short, broad, and depressed. There is a single prefrontal, and only one pair of chin shields.
The dorsal scales, which are arranged in 17 rows throughout the entire length of the body, are smooth on the neck, feebly keeled at midbody, and strongly keeled on the tail. Adults of O. andersonii have a total length (including tail) of 38–46 cm (15–18 in). The tail is 15–20 % of the total length.
O. andersonii is oviparous. Boulenger GA (1888). "Description of two new Snakes from Hongkong, and Note... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Hong Kong | 🇨🇳 China |
With luck
About 10% of wildlife watchers report an Anderson's Mountain Keelback sighting in Hong Kong on a given day, based on 26 verified sightings from GBIF citizen-science data. It is the 25th most-seen of the 43 reptiles 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.
January and May–October
In those months about 10% of wildlife watchers report an Anderson's Mountain Keelback in Hong Kong on a given day, against under 5% in February–April and November–December, the lowest months.
Between 8 and 11 pm
Across all the parks we cover, that three-hour window holds the most Anderson's Mountain Keelback sightings with a recorded time, and about 9 in 10 of them come between 6 pm and 6 am: it is mostly seen at night.
Only Hong Kong, in our data
Hong Kong is the only city on Wallace's Line with enough records to rate Anderson's Mountain Keelback sightings: about 10% of wildlife watchers there report one on a given day.
GBIF citizen-science records
It is estimated from how often the Anderson's Mountain Keelback is recorded against all the reptiles logged in Hong Kong (26 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.
