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Marine Toad: Rhinella marina
Description:
 A very large toad with skin colors ranging from brown to olive-gray and numerous warts
with dark brown tips
 Eyes adapted to a nocturnal lifestyle have horizontal slits for pupils
 Have large parotoid (poison-producing) glands behind their eyes
 Typically 4-6 in (10-15 cm) in length, but can grow to be much larger
o The largest marine toad on record was a pet in Sweden who grew to be 15
inches (38 cm) from snout to tail
 Can grow up to 2 lb (1 kg)
 Sexual dimorphism: Females are typically larger than males
In the Wild
Habitat and Range:
 Native to Central and South America
 Have been introduced into Australia, Hawaii, Philippines, Puerto Rico, and southern
Florida
 Prefer a wide variety of tropical and sub-tropical habitats with a nearby semi-permanent
source of water
 May be found in pristine forests and wetlands, but prefer deforested areas
Diet:
 Primarily carnivorous
o Feed on a wide variety of invertebrates and small vertebrates
o May also consume carrion, trash, or even dog and cat food
o In the tadpole stage, will first consume egg string remnants, then move on to
algae and detritus
Adaptations:
 When confronted by a predator, marine toads can excrete a milky toxin from their
parotoid glands which can cause twitching, vomiting, and death in small- to mediumsized predators
 Unique among anurans (frogs and toads), marine toads are able to hunt and see prey
items that are not moving
o Also known to lie in wait near artificial lights, such as a lamppost, in order to
ambush insects attracted to the light
Lifespan:
 Typically live 5-15 years
Ecosystem relationships:
 Predators:
o In native areas, a wide variety of predators consume marine toads in both their
7/19/2013
The Maryland Zoo in Baltimore
Marine Toad: Rhinella marina
tadpole and adult stages, including spiders, snakes, birds of prey, and small- to
medium-sized carnivorous mammals
o In areas where the marine toad has been introduced, many of the same types of
animals (spiders, snakes, etc.) consume them
 Historically, these animals have been unable to consume marine toads
due to the toads’ poison. However, many predatory species are
developing resistance to the toxins, or learning to avoid the poison sacs
altogether.
Reproduction:
 Able to reproduce nearly any time of the year
 Lay eggs in characteristic long chains in either slow or still water
 Typical clutches range from 8,000-30,000 eggs laid at a single time
o Very large, healthy females can lay in excess of 40,000 eggs
 Incubation lasts 2-7 days
o After eggs are fertilized, no further parental care is offered
o Large number of offspring ensure that some of the young will survive
 Reach sexual maturity at 2-4 years of age
Activity:
 Primarily nocturnal
o Metamorph toads (juvenile toads that have recently developed legs and
terrestrial lungs) may exhibit diurnal activity to avoid predation by larger,
cannibalistic toads
Other “fun facts”:
 Commonly known as cane toads
 Marine toads were classified in the Bufo genus from their description in 1758 until 2006,
when DNA analysis placed them in the Rhinella genus, which includes nearly 80 other
South American toads
 Marine toads are one of the few known amphibians to eat plant matter, carrion, and
refuse as adults. Most amphibians solely consume live prey.
Conservation Status and Threats:
 Listed on the IUCN Red List as Least Concern
o The marine toad has a very wide distribution that has been aided by its
introduction to several new areas
o The toad’s diverse diet and highly toxic skin means that it has no trouble finding
food while having an effective deterrent to native predators
 Threatened by:
o The Global Amphibian Crisis
 Worldwide decline in wild populations of frogs, toads and salamanders
observed in the past several decades
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The Maryland Zoo in Baltimore
Marine Toad: Rhinella marina
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More than one-third of the nearly 6,000 amphibian species known to
science are currently at risk of extinction
 Amphibians are an environmental indicator species – they are susceptible
to changes in the ecosystem due to their permeable skin and ties to both
land and water
Marine toads are a notorious example of a successful invasive species. Originally
introduced to Australia to control an invasive pest, the sugar cane beetle, marine toads
quickly proved to be highly adaptive and prolific eaters who could consume most
animals smaller than itself while being highly resistant to predation.
o An invasive species of local concern is the snakehead fish, which, like the marine
toad, is a highly adaptive, voracious eater capable of reproducing very quickly
o Other local invasive species include the nutria, zebra mussel, and emerald ash
borer
The marine toad invasion has had several consequences
o They have displaced existing Australian amphibians, who can neither eat as
much nor reproduce as quickly as the marine toad
o Their rapid expansion in range has threatened small vertebrate species, who
have proved to be an easy food source
o They can carry amphibian diseases, including the chytrid fungus
 Chytrid is a fungus deadly to amphibians which is thought to be partially
responsible for the worldwide decline of amphibian species
o Several species that can consume marine toads have experienced population
loss due to the toxicity of their poison, ranging from native snakes and the
possum- like quolls to domestic cats and dogs
75 different unique Australian animals are considered “at risk” due to the invasion of
toxic marine toads
o These species include both types of Australian crocodiles, all 14 species of
Australian tortoise, about half of the “dragon” species found in Australia, and
85% of the monitor lizard species unique to Australia
o In particular, the Northern Quoll is at risk, and has lost about 95% of its
population since 1980, mainly due to ingestion of the marine toad’s toxins
At the Zoo

Hoorah (male) hatched in 2005. The Maryland Zoo acquired him from the Fort Worth
Zoo in the spring of 2014.

Make environmentally responsible lifestyle decisions to help conserve habitat –
conserve energy, reduce litter and pollution
o Support rain forest conservation by recycling paper and purchasing sustainably
harvested plant and animal products
Do your research before buying a pet
o Make sure you are not purchasing a wild-caught individual – captive-bred frog
What We Can Do
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The Maryland Zoo in Baltimore
Marine Toad: Rhinella marina
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and toad species are often easy to find
o Make sure you know how to properly care for any animal before you decide to
buy it as a pet
 Some things to consider include adequate housing, diet, temperature
requirements, and lifespan
 Some pets also require a lot of time and money to be properly cared for
o If you find that a pet is too difficult to care for, donate it to a shelter. Turning
captive exotic animals loose into a non-native environment can have serious
repercussions.
We can start in our own backyard!
o Sit outside and listen closely to the sound of frog calls in the evening. These are
the frogs nearest to you.
o Provide them with habitat by avoiding the temptation to over-landscape
o Leave some woods, water, and even tall weeds undisturbed, and go easy on the
pesticide and fertilizer!
Discourage the presence of invasive species and encourage native wildlife
o Build a bat box or owl house to promote the presence of natural predators and
increase biodiversity in your own backyard
o “Bayscape” your yard—when planting flowers, shrubs, and trees, use native
species that encourage animals naturally found in Maryland to visit your
property
o If you find an unusual plant or animal, call the Department of Natural Resources
to determine if the species is invasive, and the best method for removal
References:
 http://seaworld.org/en/animal-info/animal-bytes/amphibians/marine-toad/
 http://www.iucnredlist.org/details/41065/0
 http://animaldiversity.ummz.umich.edu/site/accounts/information/Rhinella_marina.
html
 http://www.daff.qld.gov.au/__data/assets/pdf_file/0014/73112/IPA-Cane-Toad-RiskAssessment.pdf
 http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=77
3237
 Mattison, Chris. (1987). Frogs & Toads of the World. New York: Facts on File.
7/19/2013
The Maryland Zoo in Baltimore