Plants and Animals

Ambystoma opacum Marbled salamander

species photo
J. A. Fowler

Key Characteristics

The Marbled Salamander is a medium-sized (3.4 - 5 inches adult length), thick-bodied salamander with white or gray bands across a black to dark brown-black body. The belly may be black or brownish black, occasionally with some light speckling. Newly transformed juveniles are brown or black with scattered light markings which may start out yellowish and become bluish to silvery white once out of the water. The juveniles acquire the crossbanded pattern of the adults after several weeks or months.

Status and Rank

US Status: No Status/Not Listed
State Status: E - Endangered (legally protected)
Global Rank: G5 - Secure
State Rank: S1 - Critically imperiled


CountyNumber of OccurrencesYear Last Observed
Allegan 2 1989
Berrien 1 1950
Van Buren 1 1966

Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


Marbled salamanders are most common in moist lowland forests but also can occur in upland forests and dry, forested rocky hillsides. Marbled salamanders are one of only two Ambystoma salamander species that breeds and lays its eggs on land. Unlike other salamanders, marbled salamanders breed in the fall. From late September through October, the adults migrate at night to edges of forested vernal ponds, which typically dry up during the summer. Marbled salamanders are rarely seen outside of the breeding season and spend most of their time hidden beneath logs, rocks, and leaf litter or below ground in tunnels dug by small mammals. Female lay their eggs in small cavities beneath moss, fallen bark, a rotted log or other cover generally along the edge or sides of a dry or reduced pond bed that refills with fall or winter rains. The eggs hatch when the breeding pond is flooded.

Specific Habitat Needs

Downed woody debris needed in: Dry southern forestDry-mesic southern forestFloodplain forestMesic southern forestSouthern hardwood swamp.

Natural Community Types

For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Management Recommendations

One of the greatest threats to the Marbled Salamander is loss of bottomland hardwoods and associated vernal ponds. Protecting known Marbled Salamander sites and maintaining suitable habitat at these sites are essential for conservation of this species. Maintaining and/or constructing a complex of natural and/or artificial vernal ponds in suitable forested habitats would provide breeding, foraging and dispersal habitat for this species. Ponds should not freeze completely during the winter and hold water until at least May or June. Breeding ponds also should remain free of fish. Although Marbled Salamanders also can occur in drier habitats, maintaining cool, moist microenvironments and sufficient leaf litter and woody debris on the forest floor is still important for providing cover and foraging habitat for juveniles and adults. In general, partial harvests and long rotation cycles would benefit salamander populations.

Active Period

Active from first week of November to fourth week of October

Breeding from fourth week of September to fourth week of October

Survey Methods

Surveys for Marbled Salamanders can be conducted during the fall breeding season and during juvenile emergence in late spring or early summer. Visual surveys for adults migrating to or congregating at breeding ponds can be conducted in the fall from late September through October during or immediately after rainy evenings or nights. Drift fences with or without pitfall traps also can be installed around breeding sites to survey for adult Marbled Salamanders during the fall breeding season and newly transformed juveniles dispersing from breeding sites in late spring or early summer. Surveys should be conducted on multiple evenings or nights during the breeding season, and drift fences should be checked daily/nightly or more frequently if possible, especially if pitfall traps are used. Aquatic larval surveys also can be conducted in the fall, late winter and early spring before the larvae transform into juveniles and leave the breeding ponds using minnow traps, funnel traps and/or dip nets. Larvae should be photo documented and verified by a species expert.

Drift fence trapping with or without pitfall traps

Survey Period: From fourth week of September to fourth week of October

Time of Day: Night
Humidity: Humid
Precipitation: Rainy
Wind: Light Breeze

Drift fence trapping with pitfall traps

Survey Period: From first week of May to fourth week of June

Time of Day: Night
Humidity: Humid
Precipitation: Rainy
Wind: Light Breeze

Visual encounter surveys

Survey Period: From fourth week of September to fourth week of October

Time of Day: Night
Humidity: Humid
Precipitation: Rainy
Wind: Light Breeze


Survey References

  • Gibbons, J.W. and R.D. Semlitsch. 1981. Terrestrial drift fences with pitfall traps: An effective technique for quantitative sampling of animal populations. Brimleyana 7:1-16.
  • Heyer, W.R., M.A. Donnelly, R.W. McDiarmid, L.C. Hayek, and M.S. Foster, eds. 1994. Measuring and Monitoring Biological Diversity: Standard Methods for Amphibians. Smithsonian Institution Press, Washington D.C. 364pp.
  • Karns, D.R. 1986. Field Herpetology: Methods for the Study of Amphibians and Reptiles in Minnesota. Occ. Pap. No. 18. J.F. Bell Museum of Natural History, University of Minnesota, Minneapolis.

Technical References

  • deMaynadier, P.G. and M.L. Hunter, Jr. 1995. The relationship between forest management and amphibian ecology: A review of the North American literature. Environmental Review 3:230-261
  • Harding, J.H. 1997.Amphibians and Reptiles of the Great Lakes Region. The University of Michigan Press, Ann Arbor. 378pp.
  • Minton, S.A. 1972. Amphibians and Reptiles of Indiana. Indiana Academy of Science, Indianapolis. 3: 346pp.
  • Noble, G.K. and M.K. Brady. 1933. Observations on the life history of the marbled salamander, Ambystoma opacum (Gravenhorst). Zoologica 11(8):89-132.
  • Petranka, J.W. 1998. Salamanders of the United States and Canada. Smithsonian Institution Press, Washington, D.C. 587pp.
  • Pfingsten, R.A. and F.L. Downs. 1989. Salamanders of Ohio. Bulletin of the Ohio Biological Survey 7(2):1-315.
  • Smith, P.W. 1961. The amphibians and reptiles of Illinois. Illinois Natural History Survey, Carbondale. Bulletin No. 28. 298 pp.

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