Strawberry Poison Dart Frog (Oophaga pumilio): Colors and Facts

Appearance: the “blue jeans” frog

The strawberry poison dart frog, also called the strawberry poison frog or blue jeans frog, has a compact body, smooth glossy skin and fairly large dark eyes on the sides of the head. Its fingers and toes are not webbed. The skin is packed with glands that store toxins taken from its food.

The best-known form, found across Costa Rica and Nicaragua, is bright strawberry red with blue or blackish-blue legs, which gives the species its nickname. The back may have small dark spots or flecks. Males and females look alike.

The frog’s names describe its size and its tadpoles. Pumilio is Latin for “dwarf,” and Oophaga means “egg eater,” because the tadpoles of this genus feed on eggs. It was long known as Dendrobates pumilio, a name that is still sometimes used. Genetic studies suggest that its closest relatives are two other Oophaga species, O. arborea of Panama and O. sylvatica of Colombia and Ecuador, and that the genus diversified relatively recently, after the Isthmus of Panama formed about 3–5 million years ago.

Color morphs of Bocas del Toro

Few vertebrates vary in color as much as this frog. Scientists recognize roughly 15–30 color morphs, most of which breed true, meaning that frogs of each population look like their parents. The greatest variety is found in the Bocas del Toro Archipelago on the Caribbean coast of Panama, where nearby islands and peninsulas have frogs of strikingly different colors.

Morphs can be red, orange, yellow, green, blue, white or almost black, plain or covered in spots. Some island populations are largely blue, while frogs from the Punta Laurel area are mostly green with paler legs. Island populations were cut off from the mainland and from one another when sea levels rose after the last ice age, and their colors have diverged since then.

Why so many colors? Bright color works as a warning to predators, especially birds. Females also tend to prefer mates of their own color, which may help keep morphs distinct. Our article on why poison dart frogs are so colorful looks at the evidence.

How big is a strawberry poison dart frog?

It is one of the smaller poison frogs. Adults measure only about 17–24 mm (0.7–0.9 in) from snout to vent, about the length of a fingertip, and weigh roughly 1 g (0.04 oz).

Habitat and range

Strawberry poison dart frogs live in Central America, mainly on the Caribbean side of the isthmus, from eastern Nicaragua through Costa Rica to northwestern Panama. They occur from sea level to about 940 m (3,100 ft) in Nicaragua and to about 500 m (1,600 ft) in Panama.

Their home is the floor of humid lowland and foothill rainforest. They live mostly in the leaf litter but often climb onto roots, logs, vines and low branches, especially to call or to reach bromeliads, the water-holding plants they use as tadpole nurseries.

Unlike many forest frogs, they cope well with disturbed land. Large populations live in cacao and banana groves, and they are common around field stations, gardens and trails in places such as La Selva Biological Station in Costa Rica and the islands of Bocas del Toro. Any place where they live needs moist ground and plenty of small water-filled plants or tree holes.

Diet and toxins

Strawberry poison dart frogs eat tiny arthropods, mainly ants and mites, along with small beetles and other leaf-litter invertebrates. They are active foragers, snapping up prey with the tongue: juveniles take about 7 prey items an hour and adults about 14.

Their food is also their weapon. Certain ants and soil mites contain alkaloid chemicals, which the frogs absorb and store in their skin glands. More than 230 different alkaloids have been found in this species, including the pumiliotoxins, a group named after the frog itself. Pumiliotoxins affect nerve and muscle function and can cause convulsions and paralysis in small predators. The frogs cannot make these compounds themselves, so captive-bred frogs raised on fruit flies are not toxic. Find out more in why poison dart frogs are poisonous.

The strawberry poison frog is the most toxic member of its genus but much less toxic than the golden poison frog of Colombia, which carries batrachotoxin. Toxin levels vary between populations and individuals depending on what the frogs eat, and adult females usually carry more alkaloids than males. Mothers even pass alkaloids to their young through the eggs they feed them, so tadpoles that receive these meals are chemically protected too.

Behavior: territorial calling males

These frogs are active by day, especially in the morning, and are easy to see thanks to their colors. Males call from perches such as logs, roots and low leaves. The call is a series of short buzzy chirps, with about 5–9 notes per second, lasting roughly 5–30 seconds. It advertises the territory to other males and attracts females.

Male territories are tiny. At La Selva in Costa Rica, males defended areas of only about 0.25–4.8 square meters (3–52 sq ft), containing calling perches, feeding spots and tadpole-rearing sites, within home ranges of about 6–16 square meters. If an intruder answers a resident’s call and approaches, the two males wrestle, sometimes for up to 20 minutes, until one is pinned and leaves.

Females do not defend calling sites. They space themselves out according to the availability of tadpole-rearing sites such as bromeliads.

Reproduction and parental care

Strawberry poison dart frogs can breed through much of the year when conditions are wet, with a breeding season of about 8–10 months. A female follows a male’s calls, the pair court with mutual touching, and she lays a clutch of about 3–5 eggs in moist leaf litter or on a leaf. Unlike most frogs, they do not use the tight mating embrace called amplexus; the eggs are fertilized externally.

The male guards the clutch for about 10–14 days and keeps it moist by carrying water to it in his cloaca. When the eggs hatch, the female takes over. She lets the tadpoles wriggle onto her back and carries them, one or a few at a time, to separate small pools, often the water in the leaf bases of bromeliads, leaving one tadpole in each. She then returns regularly, every day or every few days, to lay unfertilized eggs into each pool, and the tadpoles eat nothing else. After about 6–8 weeks, each tadpole transforms into a tiny froglet.

This devoted care is described in detail in how poison frogs raise their tadpoles. Females can care for only about 4–6 tadpoles at a time, and only a small share of eggs, roughly 5–12%, survive to the tadpole stage.

Lifespan and predators

Little is known about how long strawberry poison dart frogs live in the wild. Frogs reach maturity at about 10 months old. In zoos, poison dart frogs commonly live about 8–15 years depending on the species, and a related dart frog has lived 17 years in captivity.

Thanks to their toxins and warning colors, adults have few predators. Many birds avoid them, and experiments with clay model frogs in Costa Rica showed that brown models were attacked more often than red-and-blue ones. A notable exception is the fire-bellied snake (Erythrolamprus epinephalus), which can tolerate poison frog toxins. Eggs and tadpoles are far more vulnerable, and they are eaten by spiders, insects and other frogs.

Conservation status

The IUCN Red List classes the strawberry poison dart frog as Least Concern (assessed in 2015). It has a fairly large range, is common in many places and thrives in some human-altered habitats, such as cacao groves.

Local threats include forest clearance and collection for the pet trade. In the 1990s, large numbers were exported to the United States and Europe, and smuggling of rare color morphs remains a problem. Like the other brightly colored poison frog genera, the genus Oophaga is listed on CITES Appendix II, which regulates international trade. Because its tadpoles need small pools in plants, the species could also be sensitive to habitat change and drying caused by a warming climate.

Myths and facts

Myth: strawberry poison frogs were used to poison blowgun darts. Only three species, all in the genus Phyllobates from Colombia, are known to have been used by Indigenous hunters to poison darts, including the golden poison frog. The “dart” name was later applied to the whole family; see why they are called poison dart frogs.

Myth: touching one will kill you. Its toxins are meant to deter small predators, and no human deaths are known. Still, wild frogs should be watched rather than handled, both for their sake and to avoid irritation from the skin secretions.

Fact: the mother feeds her tadpoles. Feeding offspring with unfertilized eggs is rare among frogs, and the strawberry poison frog is one of the best-studied examples.