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Rhinella marinaCane Toad

By Ryan Hilgris

Geographic Range

The natural range of Rhinella marina is from the Rio Grande Valley of Texas south to the Central Amazon and southeastern Peru. This toad has been introduced into the Caribbean Islands, South Florida (Key West and Stock islands, Tampa Bay, Hillsborough, Dade and Broward counties), the Hawaiian islands, and Australia's east coast (East Queensland and Coastal New South Wales). Rhinella marina has been called one of the 100 worst invasive species worldwide by the Invasive Species Specialist Group. (Aguirre and Poss, 1999; Cameron, 2002; Invasive Species Specialist Group, 2005)

Habitat

Rhinella marina is a tropical species that prefers forested areas with semi-permanent water nearby (Cogger 1983). (Cogger, 1983)

Physical Description

Rhinella marina has a grey olive brown dorsal skin with many warts ending in dark brown caps. The ventral skin tends to be a whitish yellow with dark brown speckles or mottles and is granular. Rhinella marina possesses huge 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. Rhinella marina, like other nocturnal species, has horizontal pupils. Rhinella marina can reach a maximum length of 238 millimeters, although generally is approximately 150 to 175 millimeters. (Cogger, 1983)

  • Sexual Dimorphism
  • sexes alike
  • Average mass
    106.25 g
    3.74 oz
    AnAge
  • Range length
    150 to 238 mm
    5.91 to 9.37 in
  • Average basal metabolic rate
    0.0303 W
    AnAge

Development

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 (Bureau of Rural Sciences 1998).

Reproduction

Males congregate in temporary or permanent still or slow moving water and call for mates. More than one male may fertilize the eggs of a single female, and a particularly successful males may fertilize the eggs of multiple females in a breeding season. (Bureau of Rural Sciences, 1998)

Rhinella marina is able to reproduce nearly year round. The females are able to lay eggs after their second year. Eggs are laid in long jelly-like strings on rocks, debris, or emergent vegetation; in excess of 30,000 eggs at a time. The eggs hatch in 2 to 7 days. (Bureau of Rural Sciences, 1998)

  • Breeding interval
    These toads breed once yearly.
  • Range number of offspring
    30,000 (high)
  • Range time to hatching
    2 to 7 days

Once the eggs are fertilized and arrayed in the water, there is no further parental care.

  • Parental Investment
  • pre-fertilization
    • provisioning

Lifespan/Longevity

Rhinella marina is a relatively long-lived toad, reaching ages up to ten years (Cogger 1983). (Cogger, 1983)

Behavior

The cane toad sits in an upright position when it moves, it hops in short fast hops. During cold or dry seasons it will remain inactive in shallow excavations beneath ground cover. When confronted by a predator, it is able to secrete bufotoxin from the paratoid and other glands on the back in the form of white viscous fluid. This toxic fluid is largely comprised of cardioactive substances. If a predator ingests these toxins, or they contact mucous membranes, they may cause profuse salivation, twitching, vomiting; shallow breathing and collapse of the hind limbs. This toxin can cause temporary paralysis or even death in some predators, including dogs. (Bureau of Rural Sciences, 1998)

Communication and Perception

Food Habits

Rhinella marina forages primarily nocturnally in mature forests and roadways. It feeds on ants, beetles, and earwigs in southern Florida, but has been found with dragonflies, grasshoppers, truebugs, crustaceans, gastropods, plant matter and even dog and cat food in their stomachs (Krakauer 1968). (Krakauer, 1968)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods

Economic Importance for Humans: Negative

This toad is considered the most widely-introduced amphibian species in the world. People have tried to use it to control insects such as the greybacked cane beetle, Lepidoderma albohirtum which threatened sugar cane production. However, there is no evidence that it has controlled any pest in Australia and it is now considered a pest species itself in its introduced range of Australia and on Pacific and Caribbean Islands. It preys on and outcompetes native amphibians and also causes predator declines, since these predators have no natural immunity to the bufotoxin it secretes. (Bureau of Rural Sciences 1998, Aguirre and Poss 1999). (Aguirre and Poss, 1999; Bureau of Rural Sciences, 1998)

  • Negative Impacts
  • injures humans
  • household pest

Conservation Status

In their native range cane toads are common, and not considered in need of special conservation efforts. Cane toads are considered one of the world's top 100 most widely-introduced species. Where they have been introduced they are considered pests, and targets of extermination efforts. (Invasive Species Specialist Group, 2005)

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Ryan Hilgris (author), Michigan State University, James Harding (editor), Michigan State University.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

choruses

to jointly display, usually with sounds, at the same time as two or more other individuals of the same or different species

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

insectivore

An animal that eats mainly insects or spiders.

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

poisonous

an animal which has a substance capable of killing, injuring, or impairing other animals through its chemical action (for example, the skin of poison dart frogs).

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

saltatorial

specialized for leaping or bounding locomotion; jumps or hops.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

References

Aguirre, W., S. Poss. 1999. "Indigenous Species in the Gulf of Mexico Ecosystem : Bufo marinus" (On-line). Accessed December 10, 1999 at http://museum.ims.usm.edu/~musweb/nis/Bufo_marinus.html.

Bureau of Rural Sciences, C. 1998. "Commercial Use of Wild Animals: Cane Toad" (On-line). Accessed 19 June 2000 at http://www.altgreen.com.au/wildlife/cuowa/cuwa19.html.

Cameron, E. 2002. "Cane Toads, Giant Toads or Marine Toads" (On-line). Australian Museum Online. Accessed July 28, 2005 at http://www.amonline.net.au/factsheets/canetoad.htm.

Cogger, H. 1983. Reptiles and Amphibians of Australia. Sanibel, Florida: Ralph Curtis Press.

Invasive Species Specialist Group, 2005. "Bufo marinus" (On-line). Global Invasive Species Database. Accessed July 28, 2005 at http://www.issg.org/database/species/ecology.asp?si=113&fr=1&sts=.

Krakauer, T. 1968. The Ecology of the Neotropical Toad, Bufo marinus in southern Florida. Herpetologica, 24(3): 214-221.

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