Vipera seoanei
Silhouette: Alex Slavenko · PhyloPic
In 3 days ~40% in a week ~70%
Common names: Baskian viper, Iberian cross adder, Portuguese viper, Seoane's viper. Vipera seoanei is a venomous viper species native to extreme southwestern France and the northern regions of Spain and Portugal. Two subspecies are recognized as being valid, including the nominate race described here.
The specific name, seoanei, is in honor of Spanish naturalist Víctor López Seoane y Pardo-Montenegro. Adults of Vipera seoanei may grow to a total length (tail included) of 75 cm (30 in), but usually less. This is a highly polymorphic species for which four main color-pattern types have been described:
A: well-developed, brown zigzig pattern down the back, very much like V. berus, set against a beige or light-gray ground color. B: roughly twin-striped pattern, with the ground color expressed as two narrow, straight, dorsolateral longitudinal lines along the body. Resembles V. kaznakovi to some degree.
C: uniform brownish morph with no pattern. Vipera seoanei is found in extreme southwestern France and the northern regions of Spain and Portugal. The type locality is given... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Picos de Europa National Park | 🇪🇸 Spain | |
| 2 | Pyrénées National Park | 🇫🇷 France |
Possible
About 20% of wildlife watchers report a Seoane's Viper sighting in Pyrénées National Park on a given day, based on 129 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 11th most-seen of the 22 reptiles we can rate there. Over three days the chance rises to about 40%, and over a week to about 70%, if each day is a fresh chance.
April–June, August and October
In those months about 20% of wildlife watchers report a Seoane's Viper in Pyrénées National Park on a given day, against under 5% in December to March, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Seoane's Viper sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
2nd of 2
Of the 2 parks where we can rate Seoane's Viper sightings, Pyrénées National Park ranks 2nd at about 20%. The best odds are in Picos de Europa National Park (Spain, about 40%).
GBIF citizen-science records
It is estimated from how often the Seoane's Viper is recorded against all the reptiles logged in Pyrénées National Park (129 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.
