Blue Jeans frog

Oophaga pumilio (Schmidt, 1857)

Also known / common namesSpanish – Rana venenosa fresa, Rana Roja, “Blue-jeans” frog; Bribri – Bríbri-kré!; Cabécar – Sa-kra

Blue Jeans frog(s) General Description

Tiny dendrobatid (snout-vent length 17–24 mm; mass ≈ 1–2 g) with extreme colour polymorphism: the best-known morph shows a bright scarlet head + body contrasting with cobalt-blue limbs (“blue-jeans”), but populations range from solid orange to green-spotted yellow. Skin granular, loaded with lipophilic alkaloids that impart a slightly shiny texture. Iris dark bronze; tympanum distinct. Fingers unwebbed, toes basally webbed; adhesive discs enlarged for canopy climbing. Females 5–10 % larger than males. Tadpoles grey-brown, laterally compressed with transparent fins.

Has Sexual Diamorphism?

  • Yes

Females larger; males have swollen third finger pads and emit series of “buzz-chirp” advertisement calls.

LIFE‑HISTORY & VITAL STATISTICS OF THE Blue Jeans frog(S)

Average Height / Length / Diameter

Males 1.9 cm; females 2.2 cm SVL

Average Adult Weight / Mass

1.5gr

Typical Lifespan / Longevity

4–6 yr wild; up to 12 yr captivit

Typical Lifespan / Longevity for males

4–6 yr wild; up to 12 yr captivit

Typical Lifespan / Longevity for Females

4–6 yr wild; up to 12 yr captivit

Age at Sexual Maturity

≈ 10 mo (both sexes)

Breading Season

Extended rainy season (≈ February/March – October); peaks May–August

Gestation

Reproductive Outcome

3–6 eggs clutch⁻¹; up to 4 clutches yr⁻¹ kept moist by the male

Ecology and Behaviour for Blue Jeans frog(s)

Tiny dendrobatid (snout-vent length 17–24 mm; mass ≈ 1–2 g) with extreme colour polymorphism: the best-known morph shows a bright scarlet head + body contrasting with cobalt-blue limbs (“blue-jeans”), but populations range from solid orange to green-spotted yellow. Skin granular, loaded with lipophilic alkaloids that impart a slightly shiny texture. Iris dark bronze; tympanum distinct. Fingers unwebbed, toes basally webbed; adhesive discs enlarged for canopy climbing. Females 5–10 % larger than males. Tadpoles grey-brown, laterally compressed with transparent fins.

Habitat

Humid lowland and premontane rain forest (0–700 m) on the Caribbean slope and south-Pacific foothills; common in forest edges, cacao/shade-coffee plantations, and coastal thickets near bromeliad-rich trees

Trophic Chain

Diurnal leaf-litter insectivore specialised on mites & formicine ants—the dietary source of pumiliotoxins.

Interespecies relationships noted for Blue Jeans frog

Mutualism + / +

Bromeliads receive nutrients from tadpole waste; frog gains nursery pools.

Symbiosis +/+

Skin bacteria (Pseudomonas spp.) inhibit chytrid fungus; bacteria gain habitat.

Commensalism +/0

Tiny phorid flies lay eggs on leftover jelly; frog unaffected.

Inquilinism + / 0

Micro-crustaceans live in tadpole bromeliad pools, feeding on detritus.

Phoresy +/0

No record

Tanatocresis +/0

Decomposed egg clutches fertilise leaf surfaces, boosting epiphytic algae.

Parasitism + / –

Nematode (Rhabdias) infects lungs, reducing call rate.

Predation + / –

Preyed on by cat-eyed snakes (Leptodeira), spiders; frog predates ants/mites.

Amensalism 0 / –

Alkaloids on shed skin deter growth of neighboring fungi without benefiting frog post-moult.

Competition -/-

Competes with Craugastor fitzingeri for leaf-litter prey during dry spells.

Social behaviour of Blue Jeans frog

Social Structure & Behaviour

  • Territorial males (1–2 m²) call from low vegetation; engage in wrestling bouts.

  • Female inspects clutch daily; after hatching transports each tadpole on her dorsum to separate bromeliad axil.

  • Acoustic communication: single-pulse “buzz” (≈ 3.5 kHz) repeated every 6–8 s; visual flagging (arm-waving) in noisy streams.

Distribution and Sighthings ofBlue Jeans frog(s) in Costa Rica

General Regions of Costa Rica where to find Blue Jeans frogs

Tropical
Tropical rainforest (Caribbean and North Pacific slopes)

National Parks and Reserves of Costa Rica where to find Blue Jeans frogs

Parque Nacional Barbilla
Parque Nacional Braulio Carrillo
Parque Nacional Cahuita
Parque Nacional Juan Castro Blanco
Parque Nacional Tortuguero
Reserva Biológica Hitoy-Cerere
Reserva Biológica Isla del Caño
Refugio Nacional de Vida Silvestre Barra del Colorado
Refugio Nacional de Vida Silvestre Gandoca-Manzanillo

Best Time to seeBlue Jeans frog(s) in Costa Rica

Dry Season
January
February
March
April
June
July
August
September
October
November
December

Media

Videos

Sounds and calls

Taxonomy

  • Kingdom Animalia
  • Phylum Chordata
  • Class Amphibia
  • Order Anura
  • Genus Oophaga

Conservation Status

Status IUCN

  • Least Concern

Threats

⚠️Loss/fragmentation of lowland forest and bromeliad micro-habitats.
⚠️Illegal collection for the international pet trade.
⚠️Local pesticide runoff that diminishes ant/mite prey base (alkaloid source).
⚠️Climate-change-induced drying of canopy bromeliad pools.

Fun Facts

  • Over 30 colour morphs documented in Costa Rica–Panamá, a textbook case of aposematic polymorphism.

  • Tadpoles are obligate oophages—they eat only unfertilised eggs supplied by the mother.

  • Skin alkaloids deter predatory spiders, but Parson’s leaf-nosed bat (Trachops cirrhosus) tolerates toxins.

  • Females choose nearest calling male, not the loudest—reducing predation risk during mate search.

  • Featured in 2019 Costa-Rican 2 000-colones bill celebrating biodiversity.

Origins & Record

Origin Status

Native

Population trend

Stable

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External Resources

AmphibiaWeb. 2024. Oophaga pumilio species account.
Animal Diversity Web. 2023. Life-history of Oophaga pumilio
Wikipedia (rev. 2025-07). Reproduction & parental care of Oophaga pumilio.

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