Delaware is the second smallest state in the United States at just 100 miles long and 30 miles wide. Most of it lies on a low, flat coastal plain near sea level, although the land is slightly higher at the Piedmont Plateau in the north, where rolling hills can be found. To the east is the Atlantic Ocean and Delaware Bay, while the Chesapeake Bay lies to the west.
The climate here is humid and temperate, with cold winters. Despite its small area, Delaware offers a number of different habitats in which a wide variety of flora and fauna have arisen. There are fifteen species of salamander found in Delaware, which occupy various niches across different ecosystems.
This article includes descriptions of both salamanders and newts in Delaware. To learn more about the differences between these two groups of animals, check out our article Salamanders vs Newts: What’s the Difference?
Delaware Salamanders
1) Allegheny Mountain dusky salamander (Desmognathus ochrophaeus)
- Native to eastern North America
- Family: Plethodontidae
- Order: Urodela
- Conservation status: Least concern
The Allegheny Mountain dusky salamander reaches 7 – 10 cm (2.75 – 4 in) in length and has a fairly long tail, as well as fourteen costal grooves. The back is covered entirely by a wide dorsal stripe, which varies in color from yellow or orange, to red or brown – this stripe is bordered by a dark brown line on each side. The sides of this salamander are mottled brown or black, while the ventral region is paler gray.
This species is found in the Upper Delaware Region and prefers wooded streams with sandy substrate and an abundance of aquatic vegetation. Access to rocks or logs to hide under is also important to this salamander. Individuals tend to forage at night on a variety of aquatic and terrestrial invertebrates.
2) Eastern red-backed salamander (Plethodon cinereus)
- Native to eastern North America
- Family: Plethodontidae
- Order: Urodela
- Conservation status: Least concern
The length of the eastern red-backed salamander ranges from 5.7 – 10 cm (2.2 – 4 in), although maximum lengths of 12.7 cm (5 in) have been reported. This species is dark gray or black in color with a black and white belly, and individuals have between eighteen and twenty costal grooves. Several different color morphs exist within this species, the most common being red-backed (with a reddish dorsal stripe) and lead-backed (with no dorsal stripe).
Eastern red-backed salamanders hide underneath logs or rocks in moist deciduous forests, where they forage on arachnids, worms, snails, and insects and their larvae. This species may be predated on by larger salamanders, birds, snakes, and small mammals – antipredator responses of the red-backed salamander include freezing, secretion of noxious substances, and coiling up with the tail facing upwards.
Plethodon cinereus is a highly territorial species, and individuals have been observed to perform various agonistic behaviors such as raising their body off the floor, staring at their opponent, tapping their chin to the floor, and biting.
3) Four-toed salamander (Hemidactylium scutatum)
- Native to eastern North America
- Family: Plethodontidae
- Order: Urodela
- Conservation status: Least concern
Aptly named, the four-toed salamander has four toes on its hind feet as well as its fronts, which is unusual in Urodela. Individuals of this species vary in length from 5.1 – 9 cm (2 – 3.5 in), although a record length of 10.2 cm (4 in) has been reported. The coloration of the dorsum is brown, transitioning to a slightly more reddish color on the tail, while the ventral region is white with black flecks.
Adult four-toed salamanders tend to reside in hardwood or coniferous forests near fishless ponds or swamps, where they lay their eggs and the larvae subsequently develop. The larval phase is short-lived, and after metamorphosis has taken place, the juveniles move into the surrounding forests.
Like many salamander species, four-toed salamanders are able to regenerate their tails. Research has shown that alterations to the tail in larvae do not affect the tail after metamorphosis has taken place. This has been suggested to relate to the fact that the tail has a different function in larvae vs adults: in larvae, its role is in locomotion, whereas in adults it is used for the storage of fat.
4) Jefferson salamander (Ambystoma jeffersonianum)
- Native to the northeastern US
- Family: Ambystomatidae
- Order: Urodela
- Conservation status: Least concern
The Jefferson salamander is quite large, with recorded lengths varying from 12.1 – 21 cm (4.76 – 8.3 in). Distinguishing features of this species include a slender body, long toes, the presence of twelve or thirteen costal grooves, and a laterally compressed tail. In addition, this salamander has unique coloration: gray or black with an abundance of silver or blue flecks along the back, tail, and sides.
Adult Jefferson salamanders are rarely seen, as they spend most of their time hidden in burrows (usually those of rodents). However, when they are seen, sightings tend to be in deciduous woodland, usually in close proximity to wetlands where breeding takes place. Little is known about the feeding habits of this species, but they are suggested to consume soil invertebrates such as earthworms.
The Jefferson salamander can be found in the Upper Delaware Region and the Delaware Water Gap. Data collection of salamanders in Delaware has found that fewer eggs are laid in areas with roads nearby, or wetlands with a pH lower than 6.6.
5) Northern dusky salamander (Desmognathus fuscus)
- Native to eastern North America
- Family: Plethodontidae
- Order: Urodela
- Conservation status: Least concern
The northern dusky salamander reaches lengths of 6.4 – 12.7 cm (2.5 – 5 in) and has a stout build, fourteen costal grooves, and a keeled tail. Coloration varies from yellowish brown to black, and some individuals may have a dorsal stripe, while the sides display a series of lighter-colored spots.
Habitat preferences of this species include seepage hillsides and wooded streams, particularly those with a sandy substrate and plenty of aquatic vegetation. Individuals spend much of their time hiding under rocks, logs, or leaf debris, venturing out to feed on terrestrial invertebrates such as spiders, beetles, and caterpillars.
Northern dusky salamanders are predated on by snakes, small mammals, and some birds: antipredator mechanisms in this species include autotomy of the tail, and biting at their attacker. Females can be highly aggressive when guarding eggs against predators, although incidences of egg cannibalism have also been reported.
6) Northern red salamander (Pseudotrition ruber)
- Native to the eastern US
- Family: Plethodontidae
- Order: Urodela
- Conservation status: Least concern
Northern red salamanders vary in length from 10 – 15.2 cm (4 – 6 in), and have a stout build with short limbs, and sixteen or seventeen costal grooves. Coloration tends to be salmon-red, with numerous dorsal spots forming irregular lines down the back and tail, and black flecks on the chin.
This species tends to be found in the Upper Delaware Region, where it resides in forests and meadows, often next to streams. A nocturnal species, it hides in burrows during the day, and by night comes out to feed on insects, millipedes, spiders, and small insects. Larvae hide among vegetation and consume aquatic invertebrates.
Red salamanders have been suggested to mimic the coloration of the toxic red eft, a strategy that may deter attackers. However, this is not a proven theory, and the secretive nature of the red salamander implies that their coloration alone might not provide a sufficient level of protection.
7) Northern slimy salamander (Plethodon glutinosus)
- Native to the eastern US
- Family: Plethodontidae
- Order: Urodela
- Conservation status: Least concern
The maximum length of the northern slimy salamander is 17 cm (6.7 in). This species has sixteen costal grooves and is known for the sticky secretions it produces when threatened. Its skin is blue-black with silver or white spots, and the ventral region is slightly lighter, usually a grayish black.
There are several very closely related subspecies of the slimy salamander, of which the northern slimy is one. Distinguishing between these species can be difficult and usually relies on DNA analysis or considering the geographical range in which an individual was discovered. In terms of habitat, this species prefers moist woodlands or wooded ravines, where they seek refuge under rocks and logs during the day. Individuals come out at night or after rain to forage.
Some individuals reside in caves; a study has found that the diet of northern slimy salamanders in caves tends to consist of ants and beetles, while those living at the surface have a more varied diet including ants, beetles, flies, and snails.
8) Spring salamander (Gyrinophilus porphyriticus)
- Native to the eastern US
- Family: Plethodontidae
- Order: Urodela
- Conservation status: Least concern
The spring salamander ranges in length from 12.1 – 19 cm (4.8 – 7.5 in), although maximums of 23.2 cm (9.1 in) have been reported. This species has a robust build, with a laterally compressed tail, squared snout, and a pale ridge running from the eye to the tip of the snout. The skin is typically yellowish-brown, although individuals may have a slightly reddish coloration, and mottled patterns may be present. Older individuals tend to be darker in color.
As their name suggests, spring salamanders are typically found near springs or seeps, usually hiding underneath rocks or logs during the daytime. At night they venture out to hunt their prey, which consists of a variety of invertebrates and occasionally small vertebrates, such as other salamanders (adults are occasionally cannibalistic).
9) Northern two-lined salamander (Eurycea bislineata)
- Native to northeastern North America
- Family: Plethodontidae
- Order: Urodela
- Conservation status: Least concern
Northern two-lined salamanders can attain lengths of up to 12.1 cm (4.8 in) and are slender in shape with long, thin limbs. Their coloration can vary, with individuals being yellow, olive-green, bronze, or light gray – the key distinguishing feature of this species is the presence of two dark lines traveling along the dorsum, from the eyes to the tip of the tail.
This species can be found in streams, rivers, swamps, and pools, although it has also been reported to occur in moist woodland some distance from the nearest body of water. As with many salamanders, they spend a great deal of time hidden underneath rocks or logs, a habit that protects them from predators and enables them to remain moist.
When threatened, northern two-lined salamanders will become aggressive, biting, and posturing in an effort to deter predators. Some individuals will flip over in response to snakes, while others will attempt to flee – tail autotomy is also used to evade predation.
10) Eastern newt (Notophthalmus viridescens)
- Native to eastern North America
- Family: Salamandridae
- Order: Urodela
- Conservation status: Least concern
Also known as the red-spotted newt, this species is usually 5.7 – 12.2 cm (2.2 – 4.8 in) in length. It has three phases in its life: the larval stage, the eft (juvenile) stage, and the adult stage – its appearance varies considerably between these phases. The larvae are olive-green with faint spots, external gills, and a reddish-brown tail. The red eft is terrestrial and bright orange in color, with black spots on the sides. Lastly, the adult is green with black spots along the sides.
While larvae and adults are aquatic, the red eft is terrestrial, occurring in meadows and deciduous or coniferous woodland, where it feeds on spiders, mites, insects, and worms. The adult diet includes leeches, mollusks, crustaceans, and small amphibians, while larvae consume aquatic macroinvertebrates.
This species produces tetrodotoxin, which is a neurotoxin; this is many times more toxic in efts than in adult newts and serves as an effective antipredator mechanism. Garter snakes have been observed to rub and gape their mouths after attempting to capture the eastern newt.
11) Spotted salamander (Ambystoma maculatum)
- Native to the eastern US
- Family: Ambystomatidae
- Order: Urodela
- Conservation status: Least concern
The spotted salamander varies in length from 11.2 – 19.7 cm (4.4 – 7.8 in), although lengths of up to 24.8 cm (9.8 in) have been recorded. This species has twelve costal grooves and is sexually dimorphic, with males being slightly more slender than females. Adults have brown or black skin, with yellow or orange spots on the back and sides, while the underside is gray.
Ambystoma maculatum is typically found in mixed deciduous forests where it hides under objects. It is essential for this species’ skin to remain moist, as it relies heavily on cutaneous respiration, although at higher temperatures individuals may use their lungs or buccopharyngeal mucosa for respiration.
Spotted salamanders display a number of antipredator mechanisms throughout the different life stages. Eggs are covered in a thick coating to protect them against fish or other aquatic predators, while larvae use chemical cues to detect predator types and adjust their avoidance strategy. Adults may produce toxic skin secretions, bite, vocalize, or posture, in an effort to deter predators.
12) Eastern tiger salamander (Ambystoma tigrinum)
- Native to North America
- Family: Ambystomatidae
- Order: Urodela
- Conservation status: Least concern
Eastern tiger salamanders are large and capable of reaching lengths of up to 33 cm (13 in), although are more commonly found to be between 18 – 21 cm (7 – 8.3 in). They have a robust build, with a broad head and eyes set far apart, while their tail is compressed. The coloration of these salamanders is distinctive – dark brown or black, with a series of large yellow spots down the back and sides.
This species is fairly adaptable in terms of habitat, occupying areas at various altitudes, and terrestrial adults may be found in grasslands, or on woodland edges. Adults can also be neotenic and remain in aquatic habitats throughout their life – usually occupying wetland habitats where there are no fish. The diet of the eastern tiger salamander includes annelids, insects, and insect larvae.
Despite having an overall conservation status of least concern, Ambystoma tigrinum is considered endangered in Delaware. Maintenance of forests around breeding pools, to act as a buffer, has been recommended as a conservation strategy.
13) Marbled salamander (Ambystoma opacum)
- Native to the eastern US
- Family: Ambystomatidae
- Order: Urodela
- Conservation status: Least concern
Marbled salamanders are typically 9 – 10.7 cm (3.5 – 4.2 in) in length, although some individuals have been recorded at lengths of 12.7 cm (5 in). This species has black skin, with four to seven paler bands across the back and tail – these are gray in females, and white in males. There are usually eleven costal grooves.
As a fossorial species, marbled salamanders are rarely seen, although sometimes they can be found underneath logs or rocks. In terms of habitat, they are fairly flexible – occupying floodplains or woodlands, and migrating to wetlands or vernal pools during the breeding season. Adults feed on millipedes, spiders, insects, centipedes, and snails, and in turn, are predated on by mammals such as raccoons.
Marbled salamanders tend to avoid areas near roads, and prefer areas with a higher pH. This species tends to lay its eggs earlier than other members of Ambystoma, such as the Jefferson salamander and the spotted salamander, meaning that larvae are often larger and have a competitive advantage over these other species.
14) Long-tailed salamander (Eurycea longicauda)
- Native to the eastern US
- Family: Plethodontidae
- Order: Urodela
- Conservation status: Least concern
The long-tailed salamander can reach lengths of up to 19.7 cm (7.8 in), most of which is taken up by the extremely long tail, which is longer in females than in males. Individuals have fourteen costal grooves and are yellow or orange in color, with irregular lines of black spots running down the dorsum.
This species is predominantly terrestrial, with adults being found under rocks or logs near stream margins, however, they will sometimes enter the water and are competent swimmers. Individuals are usually most active in the hours just after dark, although humid or rainy conditions will also stimulate them to come out and forage. The diet of long-tailed salamanders includes spiders, mites, ticks, and pseudoscorpions.
Male and female long-tailed salamanders accumulate at breeding sites (which are usually subterranean) in late summer, where courtship takes place. It is thought that females venture even further underground to lay their eggs.
15) Mud salamander (Pseudotriton montanus)
- Native to the eastern US
- Family: Plethodontidae
- Order: Urodela
- Conservation status: Least concern
The length of the mud salamander ranges from 7.5 – 19.5 cm (3 – 7.7 in). This species has a stout build with short limbs, a short tail, and sixteen or seventeen costal grooves. Coloration varies from orange-brown to crimson, and the dorsum is covered with irregular black spots, while the underside is paler pink or orange.
As their name suggests, mud salamanders are generally found in muddy habitats: lowland seeps, wetlands, swamps, and streams at low elevations being most popular. Individuals spend much of their time undercover, usually in burrows or underneath rocks or logs. Their diet consists of a variety of invertebrates and the occasional small salamander.
Although the conservation status of the mud salamander is that of least concern, the IUCN has identified several factors that could present a threat to populations, including urbanization, logging, and tourism. However, further research and assessment are required.
