Giant Toad

Giant Toad, Cane Toad (Eng.), Sapo comun (Sp.), Bufo marinus (Sci.), Introduced, Puerto Rico and the Caribbean Islands.

Information compiled by Alan Mowbray, Interpretive Media Writer, EYNF/LEF

General Information

The Giant Toad is a tropical animal that was initially introduced into Puerto Rico and elsewhere in the Caribbean in the 1930’s by the sugar cane industry to control beetle pests. The toads adapted well to the environment and spread quickly throughout the island’s forests and sugar growing locations.

Description

Bufo marinus has a grey olive brown dorsal skin with many warts ending in dark brown caps. The ventral skin is a whitish yellow with dark brown speckles or mottles and is granular. Bufo marinus possesses huge glandular swellings in the back of the ears (paratoid glands) stretching from the anterior side of the tympanum to halfway down the back. A high bony ridge meets at the snout between the nostrils. Like other nocturnal species, it has horizontal pupils. It can reach a maximum length of 9.3 inches (238 millimeters), although typical length is 5.9 to 6.8 inches (150 to 175 millimeters). Click here to hear its call.

Habits

Males congregate in temporary or permanent still or slow moving water and call for mates.They reproduce year round. Males are able to reproduce as both sexes because they possess a rudimentary ovary that becomes operative if their testes are removed or damaged. Females are able to reproduce after their second year. Eggs are laid in long jelly-like strings on rocks, debris, or emergent vegetation in excess of 30,000 at a time. They hatch in 2 to 7 days. The eggs hatch between forty-eight hours and one week. The tadpoles tend to be small and black and aggregate in dense numbers. Tadpoles metamorphose into small toadlets identical to the adults in forty-five to fifty-five days. The giant toad sits in an upright position when it moves, it hops in short fast hops. During dry spells it will remain inactive in shallow excavations beneath ground cover. When confronted by a predator, it is able to "shoot" bufotoxin from the glands on its back in the form of white viscous venom. These bufotoxins can lead to profuse salvation, twitching; vomiting; shallow breathing and collapse of the hind limbs if bitten, ingested, or when in contact with mucous membranes. This toxin can cause temporary paralysis or even death in some small mammals and predators.
Bufo marinus is a relatively long-lived toad, reaching ages up to ten years.
Bufo marinus forages primarily nocturnally in mature forests and roadways. It feeds on ants, beetles, and earwigs but has been found to eat dragonflies, grasshoppers, truebugs, crustaceans, gastropods, plant matter and even dog and cat food.

Habitat

Bufo marinus is a tropical species that prefers forested areas with semi-permanent water nearby.

Where to look for this animal in the EYNF

In the Tabonuco section of the forest and along the El Portal Nature Trail below the El Portal Rain Forest Center.