Holbrook, 1836 (American toad)
Habitat: Terrestrial areas associated with shallow ephemeral wetlands, eddies in streams or shallow pools used for breeding.
Life History: Up to 20,000 eggs are laid during March to July depending on local climate. Sexual maturity is reached at two to three years of age.
Native Range: The Mid-Atlanticstates except for southeastern Virginia, southern New Jersey, Long Island, and the islands of Massachusetts.
Nonindigenous Range: Cuttyhunk Island, Massachusetts.
Impacts: Other than the intended shift in toad species, impacts have not been reported. B. americanus eats insects (100 per night), slugs, and earthworms; and is preyed upon by raccoons, herons, snakes, and birds of prey.
Comments: In 1976, the American toad was first documented on Cuttyhunk Island, Massachusetts and it was breeding there by 1979. It was stocked on the island after the native Bufo woodhousii fowleri was exterminated due to pesticide spraying.
(Linnaeus, 1758) (giant toad)
Habitat: Residential areas, golf courses and schoolyards. Found where food, water and basking is available such as near insect-attracting lights, wet areas for breeding, and concrete or asphalt for basking.
Life History: Bufo marinus reproduces at almost any time of the year unless the temperature is too low, laying thousands or tens-of-thousands of eggs, encased in gelatinous strings, in any temporary or permanent body of water, including brackish water.
Native Range: Northern South America, Central America, and Mexico northward to extreme southern Texas.
Nonindigenous Range: Collected along the roadside in Middlesex County, MA.
Impacts: In many nonindigenous localities, such as Florida and Hawaii, the exact impact of B. marinus on indigenous ecosystems remains unclear. Pets that eat or bite giant toads become seriously ill from the milky venom contained within the massive parotoid glands and human poisonings occur only rarely. The complex toxic secretion from these glands can be squirted into the eyes when toads are handled roughly, causing intense pain and a potential medical emergency.
Comments: Bufo marinus was introduced intentionally in the U.S. and worldwide as a misguided attempt to control insect agricultural pests, primarily in cane fields.
(Schneider, 1799) (green treefrog)
Habitat: Stream or lake borders, swamps and freshwater wetlands, but also found anywhere with moisture or water; especially common amidst aquatic vegetation.
Life History: Known as a “rain frog”, this species calls (to attract mates) during rainy or moist periods. Breeding and egg deposition occur during May to July. Eggs are laid in numerous “packets” containing five to 30 eggs with total egg yield from 300 to 500.
Native Range: Southeastern United States northward along the east coast into Maryland and Delaware.
Nonindigenous Range: Collected from a shipment of plants in Norfolk County (Massachusetts).
Impacts: No impacts are reported because the species did not become established.
LeConte, 1857 (barking treefrog)
Habitat: Pasture ponds, woodlands, and farmland. Their position within a habitat varies from high in the trees to ground level. They burrow in sandy soil during heat and drought, often in groups.
Life History: Breeding occurs during spring and summer in ponds or swamps or occasionally in brackish marshes. Females lay 1,000 or more eggs on the pond or swamp bottom, deposited singly, each in their own jelly-like envelope.
Native Range: Most of the southeastern United States with disjunct, native populations occurring in the Mid-Atlantic.
Nonindigenous Range: A nonindigenous population of H. gratiosa was documented in New Jersey during 1956 and 1957. The population persisted for approximately a decade, but is now presumed extirpated.
Impacts: No impacts were documented.
(Dumeril and Bibron, 1841) (Cuban treefrog)
Habitat: Residential and commercial areas, and freshwater wetlands.
Life History: Breeding season may last throughout most of the year in southern Florida. Females are continuously fertile, laying clutches of 1, 200 to over 16, 000 eggs. Eggs can be laid in any warm, shallow body of water, usually lacking predatory fish.
Native Range: Cuba, the Bahamas and the Cayman islands.
Nonindigenous Range: Collected from a shipment of Cuban bananas in Baltimore and from a horticulture nursery in Warrenton, VA; the species is also established in southern Florida, Hawaii, and Puerto Rico.
Impacts: It is not likely this tropical species can endure winters in the Mid-Atlantic region. Where it is established, impacts are far-reaching because it voraciously preys upon frogs and invertebrates.
Shaw, 1802 (bullfrog)
Habitat: Lakes, ponds, cattle tanks, bogs, and sluggish portions of streams and rivers.
Life History: Breed in June and July producing 10, 000 to 20,000 eggs. Tadpoles transform as quickly as 4 months in warmer climates and up to 3 years in colder locations. In colder climates, bullfrogs require year-round persistence of water for tadpoles to mature and over-winter.
Native Range: Eastern United States, but historically absent from the Cape Cod archipelago and associated islands.
Nonindigenous Range: Stocked in Nantucket, the Vineyard, and the Wellfleet Bay Sanctuary, but now established only in Wellfleet Bay Sanctuary, Massachusetts.
Impacts: In Wellfleet, Rana catesbeiana is apparently expanding its population and out-competing the native green frog (Rana clamitans). Where introduced populations have been studied in the Western U.S., adults consume birds, rodents, frogs, snakes, turtles, lizards, and bats. They are voracious eaters who will also prey on their own young.
Comments: Based on a study in western Washington, conservation of ephemeral wetlands will halt range expansions of bullfrogs. Permanently inundated wetlands are more likely to house nonindigenous species.
Schreber, 1782 (northern leopard frog)
Habitat: Streams, lakes, ponds, and wet prairies. Called the “meadow frog” due to wandering well away from water in the summer time. Individuals may congregate under submerged logs or rocks during the winter.
Life History: Lays eggs from March to May; tadpoles transform in late June to August.
Native Range: Southern Canada and the northern United States.
Nonindigenous Range: Considered nonindigenous in the Cape Cod islands, the species has been established there for decades.
Impacts: No impacts have been documented.
Comments: Specimens reportedly exhibiting atypical color patterns for Massachusetts were collected as early as 1915 from Cuttyhunk Island. The species was harvested in states like Minnesota, Vermont and Connecticut for use in classroom experiments. Once experiments were completed teachers routinely released the surviving tadpoles into the wild.
(= Rana utricularia) Cope, 1886 (southern leopard frog)
Habitat: Shallow, freshwater habitats and some slightly brackish marshes. Like its northern counterpart, the southern leopard frog can be found great distances from water, usually in grassy or vegetated areas, during the summer.
Life History: Pairs typically mate/deposit eggs at night from April to September. Eggs hatch days later.
Native Range: Southeastern U.S and surrounding states.
Nonindigenous Range: Collected from three localities in central and western Massachusetts (Sheffield, Bershire County; Ludlow, Hampden County; and Amherst, Hampshire county).
Impacts: All are presumed to be pet escapes and not established, so ecological impacts are negligible. If southern leopard frogs establish in Massachusetts, hydridization with the native northern leopard frog (Rana pipiens) could compromise ecological integrity.
(Daudin, 1802) (African clawed frog)
Habitat: Any permanent freshwater body, such as rivers, lakes, wells, swamps, and ditches.
Life History: Hundreds to over 2000 eggs are released and fertilized in the water column during nocturnal breeding; they are then deposited onto any available surface. Individuals live up to 15 years in captivity.
Native Range: Sub-Saharan Africa, but introduced throughout the world.
Nonindigenous Range: Acton Arboretum, Acton (Massachusetts) and Golf Branch Nature Center, Arlington (Virginia). Eradication measures were taken in Virginia, but it is unknown if any X. laevis migrated to other habitats before the eradication.
Impacts: Prey upon macroinvertebrates and some vertebrates.
Comments: X. laevis has long been used in laboratory research, and became established in many laboratory aquaria throughout the world in the 1950s and 1960s. Earliest reports of established nonindigenous populations of X. laevis worldwide are coincident with the end of their use in human pregnancy diagnosis.