Nature Field Guide
Yellow-bellied Sea Snake
- Spanish name
- Serpiente marina de vientre amarillo
- Scientific name
- Hydrophis platurus
What Do Pico & Tati Think?
Pico and Tati invite you to discover a reptile adapted to ocean life. Use a reference illustration to compare its swimming tail with the tail of a land snake.
Species overview
About the Yellow-bellied Sea Snake
The yellow-bellied sea snake lives in tropical Pacific waters off Costa Rica. Its usual pattern has a black or dark brown back sharply separated from a yellow underside. Its flattened tail helps it swim. Mostly yellow individuals also occur in Golfo Dulce; these belong to the same species rather than a separate card.
Identification
Key Features of the Yellow-bellied Sea Snake
Dark back and yellow underside, usually separated along the length of the body.
Flattened, paddle-shaped tail, often with contrasting dark markings.
Small head and slender neck; patterns vary between individuals.
Habitat & range
Pacific marine waters off Costa Rica, including coastal and offshore waters. A mostly yellow population occurs in the inner Golfo Dulce.
Local observations
Recorded in Costa Rican Pacific waters. This profile does not establish a particular Tamarindo sighting or guarantee a viewing location.
When to observe
Encounters vary with ocean and weather conditions. Learn using reference images or observe only from a safe location with a trained guide.
Conservation & care
Venomous. Never touch, catch or move a sea snake, including one washed onto a beach or appearing dead. Keep children and pets away, step back and tell an adult or trained guide. Do not attempt to return it to the water. Do not use color patterns to decide whether any snake is safe.
Observation activity
Draw the paddle-shaped tail from a reference illustration. Compare its shape with a land snake’s tail and discuss how it helps with swimming.
Explore by location
Central Pacific · Guanacaste · Oceanic Pacific · Puntarenas & the Gulf Islands · South Pacific · Puntarenas