American Toad Bufo americanus Christina Miller Last update: Monday, January 7, 2008.

 

Eastern American Toad, Bufo americanus americanus Sound clip: A male American Toad peeping in protest to being handled.

Taxonomy Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata Class: Amphibia Subclass: Lissamphibia Order: Anura Suborder: Neobatrachia Superfamily: Bufonoidea Family: Bufonidae Genus: Bufo Species: americanus Subspecies: americanus, charlesmithi

Experience level: Beginner (suitable as a first herp)

I. Introduction

A species frequently seen in fields, woods and backyards in the northern United States and southern Canada, it is often called the common toad. In captviity, they typically 15-20 years, but there have been captives exceeding the age of 30.

They are very uncommon in the pet trade because they are a native species, and personally I must discourage harvesting local wildlife for commercial purposes. However, collecting a few individuals for pets in a home is not necessarily detrimental to wild populations, and these are wonderfully entertaining amphibians both in the wild and in captivity. Before collecting any herp from the wild, check the local laws to see if a permit is required, and it would be a good idea to check the population status of toads in the area, as well. Local universities, wildlife conservation groups and herpetological associations can point you in the right direction to finding this kind of information. If a local population is at risk, it would certainly be better to leave the toads in the wild.


II. Taxonomy

The American toad belongs to the family Bufonidae, genus Bufo (the typical or true toads). The genus Bufo is distributed worldwide, but Frost et al 2006 redefined North American anurans and created a new genus, Anaxyrus. This suggested change has not yet been universally accepted, and the name Bufo americanus is still used almost exclusively.

There are two subspecies, the Eastern American Toad, Bufo americanus americanus (Holbrook 1836) and B. a. charlesmithi (Bragg 1954), the Dwarf American Toad.

III. Description

Eastern American Toads grow to be about 5 to 11 cm (2-4.5") SVL, but Dwarf American Toads only reach 5-9 cm (2-3.5"). They are plump, squat creatures. They range from brown to brick red, to olive green, often patterned with lighter tan or beige patterns. The back is littered with brown spots, and depending on the subspecies, these spots will have orange-red to brown warts inside them. Some specimens may have a light coloured stripe down the center of the back. A noticeable feature is the long, paratoid glands on the head that can secret a viscous, white poison when disturbed (bufotoxin). These toads have very attractive gold eyes. The belly is usually spotted, and males have a dark gray throat while females' are light gray or white.

IV. Behaviour

This terrestrial toad usually hides during the day under dirt, leaves, rocks or logs, often excavating small holes to conceal themselves in. At night they forage for insect prey.

Like most toads, they are gentle, lax creatures, however if startled they will inflate themselves with air to appear larger. They will often allow themselves to be handled, but will sometimes defecate, urinate or vocalize in protest to being picked up. When frightened, it may also excrete a white, milky poison (a bufotoxin, which is a combination of chemicals found in toads of the genus Bufo) from the long, bean-shaped paratoid glands on the back of its head. This substance has a bitter taste, and can irritate eyes, skin and mucous membranes if they come in contact with it.

V. Diet

These amphibians will thrive on a varied diet of invertebrates. Crickets, cockroaches, superworms and mealworms should be part of the diet to provide roughage, and adding soft prey like small hornworms, butterworms, and silk worms adds more nutritional variety. All prey should be gut-loaded on a nutritious diet 24-36 hours before being fed to the toad. This is to ensure that the prey you are feeding contains a variety of nutrients, as most prey is poorly fed at the pet store. Fatty prey like wax worms are nice supplements, but because of their high fat content they should be fed sparingly. Prey variety is the key to good health. Do not limit your toad's diet to just one or two different types of prey. Amphibians rely heavily on vision to find and catch food, so prey must be moving.

Young toads should have food available daily (preferably confined to a dish so that the prey is easy to find). Adults can be fed every 3-5 days, as much as they will eat in about 10 minutes is a good way to find out how much your toad will normally take. Remove uneaten food from the enclosure, as invertebrates can chew on sleeping toads.

Dietary supplement powders are a controversial topic as we are uncertain of exactly how much is needed. We cannot possibly provide the same type of nutrition that these animals have in the wild, so their use is not unfounded. Vitamin and minerals overdoses are possible, so they should be used sparingly, and gut-loading should never be replaced by supplements. Because most invertebrate prey has an inverse calcium to phosphorus ratio, consider dusting most invertebrate prey with calcium powder. Multivitamin and mineral supplements can be used less often. Gravid females should be provided more calcium in their diet to make up for calcium lost to eggshell and yolk production. My personal supplementing schedule for all of my insectivorous herps includes calcium every 1-2 meals, and a multivitamin and mineral supplement every 4-5 meals.

A shallow water dish large enough for the entire toad's body should always be available, and kept clean. The water should be changed daily (or more often if the toad has eliminated in the dish), and the dish itself should be disinfected with a mild detergent (like an antibacterial dish soap) every two weeks.

IV. Housing

Size and build: The enclosure could be as simple as an aquarium or a plastic, transparent long-style enclosure. About 38-57 L (15-20 gallons) of space is needed for an adult toad, but floor space is more important than vertical space. A cheap and practical enclosure could be a large plastic storage bin (but glass aquariums work equally well). A lid is required to ensure that toads and prey do not climb or jump out.

Housing more than one toad together can be done given there is sufficient space, the environment has enough hide spots and visual barriers, and the animals are roughly the same size. Many amphibians will readily cannibalize each other if food is scarce, or accidentally during a "feeding frenzy." Two adults could easily be housed in 57 L (20 gallons).

Example setup for an American Toad. Note the shallow water dish, earth substrate and logs, plants and rocks for cover. Both plant are Pilea (Aluminum Plant) varieties.

Cage furniture: These toads do not require climbing furniture, however obstacles that provide visual barriers and objects to burrow against are appreciated. Rocks, logs, slabs of bark and live or fake plants are all suitable. Substrate: As substrate, plain potting earth is relatively safe, simple and cheap. Be sure to select soil with no additives such as fertilizers, vermiculite or perlite. Appropriate forest soil mixes including soil, woodchips, sand and decomposing leaves are also suitable. Substrate consisting of loose chunks of material such as woodchips, crushed walnut shell and crushed corncob should be avoided, as these are generally unsuitable for amphibians for various reasons.The substrate should be a minimum of 5 cm (2") deep to allow for natural digging behaviour. Whichever substrate you use should be kept damp, a rule of thumb is that it should be wet enough to feel "wet," but when you squeeze a handful of substrate water should not drip out. Simple sheet substrates like damp paper towels or foam rubber are suitable for a temporary enclosure (such as a quarantine or hospital cage), however natural substrates that are properly maintained will help raise humidity and preserve a natural atmostphere. Recall that these toads also prefer a substrate in which they can burrow, which is important for their sense of security.

V. Water

A shallow dish of clean water is a necessity. Amphibians do not drink, but absorb water through their skin from the environment. Toads, despite their dryish-looking skin, will soak almost daily to ensure they are well-hydrated. Because water impurities will also be absorbed through the skin, water quality needs to be monitored. Water should not contain chlorine or chloramine.


VI. Heating

Daytime temperatures should range from 15-23 °C (59-73 °F), so room temperature is typically adequate. Note that these toads, like most amphibians, are very sensitive to overheating. Temperatures greater than 26 °C may be distressing, causing the toad to seek shelter, and prolonged exposure to temperatures greater than 30 °C may be fatal. (Bundy and Tracy, 1977)

Nighttime and seasonal temperature variations of a few degrees are expected. In the wild, these toads will hibernate during cooler months in the northern part of their range.

VII. Humidity

The relative humidity of the enclosure should generally range between 50-60%. Using a natural soil substrate, adding live plants and a wide, shallow water dish will help maintain humidity. Various humid microhabitats up to 100% humidity can be provided by using live plants, slabs of bark and moist sphagnum moss. The enclosure humidity will also increase periodically when it is misted, which can be done a few times a week to simulate natural rainfall.



VIII. Lighting

Provide a photoperiod of 10-14 hours, varying with the seasons. A proper day/night cycle can be achieved by using an electrical timer.

IX. Sexing

Males display a dark gray throat, while females' are light gray or white. Females also tend to be larger than males.


VI. Health

Proper husbandry is the key to good health in all amphibians. If you provide good basic care, then you will avoid the vast majority of potential health problems that amphibians can encounter in captivity.

Because American Toads are virtually all wild caught, they are undoubtedbly parasitized. The process of being captured is very stressful, and this stress can afflict the immune system and allow any normally harmless parasites to become disease-causing. A fecal exam should be performed by an experienced herp vet to determine if antiparasitic medications are needed to prevent any parasite-related health problems.

Cleanliness is of extreme importance with amphibians because of the nature of their skin. Environmental impurities and toxins are a common cause of illness in captive amphibians. Ensure that water dishes are cleaned regularly, and waste and uneaten food is promptly removed from the enclosure before spoilage can occur. Equipment cleaning should be performed without harsh chemicals like bleach- hot water and a mild dish soap are often all that is needed.

When in doubt about a health issue with your pet, do not hesitate to contact a knowledgeable reptile and amphibian veterinarian. To find a vet in your area, see the directory at the Association of Reptile and Amphibian Veterinarians website.

Glossary:

• Anuran: Any amphibian (class Amphibia) of the order Anura, which includes the frogs, toads and treefrogs. An old name for this order is Salientia.
  
• SVL: "Snout to vent length," the length of the animal from the tip of its snout to the vent, i.e. the length of the animal not including the tail.
  
• Terrestrial: Describes an animal that predominantly lives on land, or lives and dwells on the ground.

Sources:

Further Reading:

• Herptiles.net:
  • A Basic Guide to Evaluating an Amphibian's Health
  • Bufonidae: The True Toads, Harlequin Toads and Relatives
  • Handling Amphibians
  • Humidity
  • Substrate
• External:
  • Amphibian Diseases Homepage
  • ARAV: Association of Reptile and Amphibian Veterinarians
  • The Erowid Psychoactive Toad Vault: Toad Toxin