The Eastern Newt (Notophthalmus viridescens) is a common salamander found in eastern North America. These creatures have a complex life cycle with distinct stages, each having specific dietary needs. Understanding their diet at each stage is essential for their survival in the wild and responsible care in captivity.
Eastern Newt: An Overview
The Eastern Newt (Notophthalmus viridescens) is a small, semi-aquatic amphibian native to eastern North America, primarily found in southern Canada and the United States, excluding Mexico. Adult Eastern Newts are generally 2.5-5” long. They are entirely aquatic as larvae, terrestrial as red efts, and semiaquatic as adults.
As juveniles, known as Red Efts, they are reddish-orange with slightly bumpy skin and live on land for up to eight years. Adult Eastern Newts turn olive green, with bellies that reveal scattered black spots on a bright yellow background. They reach up to 5 inches in length.
Life Cycle
The Eastern Newt has a complex life cycle, including an aquatic adult stage and a terrestrial stage when it is known as the Red Eft. Although most populations have the four stages described above (aquatic egg, larva, terrestrial juvenile, and aquatic adult), environmental factors, as well as densities, can influence the timing.
- Egg Stage: Females lay between 200 and 400 single, jelly-covered eggs on submerged vegetation each season, scattering them wildly. The female newt swims away as soon as the process is finished, leaving her eggs to survive on their own. The egg hatches within three to five weeks into a brownish-green larva, which uses gills to breathe and lives in water.
- Larval Stage: Larvae do not leave the pond environment where they were hatched. The length of the larval period varies, from about two to five months. The aquatic larvae are generalist feeders that consume prey in direct proportion to their availability.
- Red Eft (Juvenile) Stage: The juvenile stage is terrestrial and begins when the larva loses its gills, develops lungs to breathe air, transforming into a Red Eft in late summer. This stage lasts two to seven years. Juvenile Eastern Newts - usually referred to as Red Efts - are smaller than adults, about one to three inches long. Red Efts, as the name implies, have bright orange or orange-red skin with two rows of dark-rimmed yellowish or orange spots on each side of the back.
- Adult Stage: A second metamorphosis occurs when the eft transforms into an adult, which remains in or near a pond for the rest of its life. The timing and nature of these stages are quite variable. Adult Eastern Newts are three to five inches long. The tail is finned and comprises about half of the total length. The upperside is usually olive green or brownish with many small black dots and two rows of red or orange spots on the back. The spots may be outlined in black. The throat, belly, and underside of the limbs are yellow. The skin of adult Eastern Newts is soft and smooth.
Dietary Habits of Eastern Newts
Eastern Newts are carnivores during all their life history stages. They are opportunistic feeders, consuming whatever is palatable and available.
Read also: Dietary Habits of Whip-poor-wills
Larval Diet
The aquatic larvae are generalist feeders, consuming prey in direct proportion to its availability. The aquatic larvae eat small invertebrates including insect larvae and fleas. Larval newts usually rely on suction feeding.
Red Eft Diet
The terrestrial Red Eft feeds on earthworms and arthropods found within leaf litter. Their menu includes mites, fly larvae, worms, land snails, and slugs. Most of their prey are found in the upper leaf litter layer, soil surface, or low vegetation. Terrestrial efts eat small invertebrates, such as snails, spring tails, and soil mites.
Adult Diet
Aquatic adults are also opportunistic predators which will eat any palatable prey they can swallow whole. They feed on aquatic insects, worms, small crustaceans, mollusks, spiders, and the eggs and larvae of other amphibians. They help keep mosquito populations in check by feeding on their larvae. Adult newts eat mainly midge larva and other aquatic immature stages of insects.
Adult Eastern Newts reportedly are active throughout the year, although activity levels probably depend on the severity of the winter. Adults are active throughout the day, foraging as they move about on pond bottoms. Eastern Newts are said to be most active in rainy weather.
Feeding Behavior
Throughout their life stages, newts use different feeding strategies. Larval newts usually rely on suction feeding, while juveniles and adults use their hyoid and lingual apparatus (along with specialized jaw muscles and teeth) to handle a broader range of prey and environments. Primarily, these creatures use suction feeding to capture prey. Suction feeding is when a newt opens its mouth to create a vacuum that draws in not only prey but also water. The main structure involved in this form of feeding is the hyoid apparatus, which is a series of connective tissues and bones in the throat. These parts lower the floor of the newt’s mouth, creating suction. When on land, a newt’s hunting method shifts slightly. They use their sticky tongue to effectively capture and feed on prey. The structure involved in this feeding behavior is the lingual apparatus. This apparatus controls the tongue and enables it to project outward to catch prey.
Read also: Red Bat Feeding Habits
Eastern Newt as Pets: Feeding Guidelines
Eastern newts are intermediate-level pet amphibians due to their semiaquatic nature and mild toxin. Eastern newts are primarily carnivores, which means that they need to eat whole animal prey in order to get the nutrition that they need. In the wild, they aren’t picky, eating just about anything that they find, from mosquito larvae to frog spawn. Over food every other day, as much food as they will eat within ~10 minutes.
Ecological Role and Conservation
Eastern Newts play an important role in the ecosystem. By consuming various invertebrates, these slippery creatures support food webs and maintain ecological balance. Specifically, suppressing populations of slugs and beetles helps maintain species balance, which helps prevent overpopulation.
The Eastern Newt is one of the most widely distributed salamanders in North America. Eastern Newts are found throughout the eastern United States, from the Canadian maritime provinces west to the Great Lakes and south to Florida, Texas, Alabama, and Georgia. The Eastern Newt is listed by the IUCN as a species of least concern; its population is considered to be stable.
However, like many other amphibian species, they are increasingly threatened by several factors including habitat fragmentation, climate change, invasive species, over-exploitation, and emergent infectious diseases. Eastern newts are highly sensitive to changes in their environment and are able to detect and respond to changes in water quality and temperature. When populations of eastern newts decline, it can be a sign of environmental stress or degradation.
Read also: Eating Habits: Eastern Coral Snake