Frog of the Week

Horned Marsupial Frog (Gastrotheca cornuta)

horned marsupial frog
Photo By Brian Gratwicke

Common Name: Horned Marsupial Frog
Scientific Name: Gastrotheca cornuta
Family: Hemiphractidae – Marsupial Frog family
Location: Colombia, Costa Rica, Ecuador, and Panama
Size: 2.8 – 3.1 inches (7 – 8 cm)

The Horned Marsupial Frog is a nocturnal species of frogs that live high in the canopy of rain forests. These frogs never have to leave the trees because they don’t lay their eggs in the water. During the breeding season, the males will call out to the females, mostly during the late afternoon and nights. Once a female selects a mate, the male will grasp the female from behind in an axillary (the male’s front arms grasping over the female’s front arms) amplexus position. The female will lay a single egg and the male will fertilize it. He will then move it into her poach on her back with his hind legs! This is why they are called marsupial frogs. The female and male will continue this cycle until all eggs are laid. The eggs are one of the largest known amphibian eggs. The female will carry the eggs in the poach for 60 – 80 days until froglets will emerge from her poach. The froglets average around .3 inches (1cm) in length at emergence.

photo by Andrew J. Crawford 

The Horned Marsupial Frog is listed by the International Union for the Conservation of Nature (IUCN) Red List as Endangered. The frogs haven’t been seen in Costa Rica in over 20 years. The primary threats to the frogs are habitat loss and chytrid fungus. Most of the beautiful forests that the frogs call home have been logged to make room for farms, houses, or just for timber industry. Chytrid Fungus, a deadly disease for frogs, has been found in the species and is to blame for some of the declines. The disease makes the skin of frogs thicker, making it harder for them to breathe until they die. Overall, better protections for the remaining forests they call home are needed or this unique frog will disappear forever.

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