Marbled Salamander (Ambystoma opacum)
- Marbled salamanders reach a length of 4 to 5 inches (10 to 12.7 cm), head and body. They have smooth, dark gray to black skin, or even deep purple above with a gray belly. Light silver to white markings are on their back. Marbled salamanders have a stocky body with a short, broad head, and a relatively short tail for a salamander — their tail is 40% of their total length. They also have short legs with four toes on their forelegs and five toes on their hind legs.
- Life History
Adult marbled salamanders eat earthworms and small insects. During the larval stages they feed on zooplankton, but as they grow, they gradually begin to feed on small insects (including mosquitoes), tadpoles and other larvae. Snakes, raccoons, ducks, and wading birds prey on marbled salamanders. Mating season is throughout the fall. These salamanders construct nests as shallow, dry depressions in pond or stream banks. Females lay 50 to 200 eggs. Eggs hatch as soon as they are covered with water, but may delay until spring if rainfall is insufficient to cover them. Larvae are about 0.75 inch (2 cm) long when hatched and metamorphose (change from larvae to adult) in four to six months. Their lifespan is about four years.
Male marbled salamanders breed near water. They emerge during winter rains and enter shallow pools to deposit sperm packets. The females arrive later, pick up the packets and fertilize their eggs internally, storing them until it is time to lay their clutch (group of eggs). The females select a point between the shallowest and deepest area of the ponds. Then they lay their eggs one at a time in a shallow depression under vegetation, encircling the eggs until the depression fills with water from spring rains. This behavior is called brooding the eggs.
Young are generally brown to black with light spots or mottling dorsally (on top) and laterally (on sides). Marbled salamanders darken as they mature. There are 24 salamander species in Texas. Salamanders are often mistaken for lizards, but they have smooth or warty skin instead of scales and have no claws on their feet.
- Riparian areas (land adjacent to water) or swampy areas with slow moving water are the marbled salamander's preferred habitat. They can usually be found under rotting logs and other vegetation.
- Marbled salamanders are widespread across the eastern half of the United States and throughout East Texas from Red River south to the Gulf of Mexico.
- The marbled salamander is a lizard-like amphibian that is seldom seen by people. One reason is that they are nocturnal (active at night), and hide by day under vegetation and rotten logs. Like all amphibians, they require water to complete their life cycle, surviving dry times by burrowing deep into the soil. Worldwide, many amphibian populations are declining or have disappeared completely. There are many possible causes for this decline — acid rain, herbicides, insecticides, fertilizers, industrial waste, habitat destruction, introduced species, bacteria, ozone depletion, and global warming. It could be a combination of any or several of these suspected causes, however much study is needed to solve the mystery, saving marbled salamanders and other amphibians. People can help by recognizing and conserving salamander habitat where possible and by supporting the study of local and global environmental change.