The Spotted Salamander, Ambystoma maculatum – Part II, Natural History

Spotted salamanders produce toxic skin secretions but are none-the-less consumed by garter snakes and hog-nosed snakes. Introduced trout, bass, goldfish and other fishes prey upon the larvae and can decimate a population in a single season.

Reproduction
Adults migrate from terrestrial burrows to temporary ponds (vernal pools, swamps, ditches, sluggish streams) in the early spring. The migration is triggered by snow-melt or warm rains, with adults sometimes crossing snow to reach their breeding sites. Males arrive at the ponds 1-6 days before females. I have observed them breeding in Westchester County, NY in mid March, when the water is quite cold. Despite this, I found that food for the larvae, in the form of aquatic insects and fairy shrimp, was abundant.

Large mixed-sex groups form at the pond bottom during courtship. Males deposit a spermatophore (a sperm-filled, jelly-coated capsule) on the pond bottom. The females take this into their cloaca (reproductive opening) and fertilization occurs internally.

The eggs are laid in compact, jelly-covered masses that are attached to twigs, plants or sunken logs. Each mass contains 50-160 eggs. The sight of 20 or more large, brilliantly marked salamanders writhing together in as they vie for breeding rights is really something to see – please write in if you’d like information as to how you might observe this for yourself.

A species of green algae, Oophila amblystomatis, frequently colonizes the egg mass, apparently supplying oxygen to the embryos and utilizing the carbon dioxide that they produce. Larvae from algae-colonized egg masses hatch earlier and exhibit less mortality than do those from algae-free masses.

The adults return to their burrows after breeding. The terrestrial habitat may be 75 – 1,000 feet from the breeding pond.

The larvae hatch in 8-60 days, depending upon water temperature, and have external gills. Transformation to the adult form takes place over a period ranging from 6 weeks to 18 months. In NY, the larvae typically leave the breeding ponds by late July or August, after which the ponds usually dry up.

Miscellaneous
Adult spotted salamanders have lungs but rely largely upon cutaneous respiration (the absorption of oxygen through the skin). The skin must remain moist if this form of respiration is to be effective – they are therefore, limited to damp habitats and rarely appear above ground except after heavy rains. They and other salamanders depend upon protective tree cover, leaf litter and fallen logs to retain soil moisture, and rapidly disappear from degraded habitats.

You can read more about spotted salamander natural history and conservation at:
http://www.globalamphibians.org/
Of course, you can also order my salamander book from That Pet Place (see above) – Thanks!