Iowa is situated in the Midwestern United States, bordered by the Missouri River to the west and the Mississippi River to the east. This state is characterized by rolling plains and cornfields with fertile land fed by many tributaries and streams, in addition to an average rainfall of 24 – 36 inches per year. Iowa is positioned in the humid continental zone and experiences hot summers, cold winters, and wet springs.
Just five species of salamander can be found in Iowa. While many of them reside in similar habitats, they each occupy their own niche in the ecosystem.
Iowa Salamanders
1) Blue-spotted salamander (Ambystoma laterale)
- Native to eastern-central North America
- Family: Ambystomatidae
- Order: Urodela
- Conservation status: Least concern
The blue-spotted salamander ranges in length from 10.1 – 14 cm (4 – 5.5 in). It has a shiny black dorsum with pale blue flecks on the sides, tail, and underside. This species has twelve costal grooves. Although rare, melanistic individuals do occasionally occur in the wild – however, these are much more susceptible to predation.
Despite the overall conservation status of the blue-spotted salamander being that of least concern, in Iowa it is considered endangered. Currently, populations are thought only to exist in Black Hawk and Linn counties. This species resides in forests, relying on areas with moist soil where they seek refuge underneath leaf litter or moss.
Threats to Ambystoma laterale include road fatalities, pollution, and loss of habitat due to agriculture. A study examining Iowa populations of the blue-spotted salamander found that in recent years the population has experienced a bottleneck effect, and as such there is now a significant amount of inbreeding. This poses a great risk to the survival of this species.
2) Tiger salamander (Ambystoma tigrinum)
- Native to the Atlantic Coast
- Family: Ambystomatidae
- Order: Urodela
- Conservation status: Least concern
The tiger salamander is the largest terrestrial salamander in North America, capable of reaching lengths of up to 36 cm (1 ft 2 in). More commonly, however, individuals are around 15 – 20 cm (5.9 – 7.9 in) in length. This salamander has a stout build with a broad head and is dark brown or gray in color with a series of dark yellow blotches and stripes wrapping around the body. The underside displays pale yellow patches.
Ambystoma tigrinum can be found statewide in Iowa, where it occupies bottomland deciduous forests, preferring areas with sandy soil. In late winter, this species migrates to ponds to reproduce – males are thought to spend longer at the pond than females, a reflection of the different roles they play.
Adult tiger salamanders feed on worms, snails, slugs, and insects. Larval individuals usually consume small crustaceans and insects, but occasional cannibalistic individuals arise in a population to prey on weaker conspecifics.
3) Small-mouthed salamander (Ambystoma texanum)
- Native to central North America
- Family: Ambystomatidae
- Order: Urodela
- Conservation status: Least concern
The small-mouthed salamander ranges in length from 10.2 – 19.1 cm (4 – 7.5 in), and as the name suggests, it has a small head and mouth. This species has 13 – 15 costal grooves and has a gray, black, or dark brown dorsum with pale tan or blue-gray flecks. The underside is dark with small pale flecks.
Ambystoma texanum can be found in the southern third of Iowa, where it occupies bottomland forests interspersed with rivers and streams. This species is likely to have entered the state from the south and may continue to expand its range further north in the future.
Small-mouthed salamanders face threats due to the conversion of bottomland forests to agriculture – the removal of trees and drying of breeding pools may result in declines in populations.
4) Eastern newt (Notophthalmus viridescens)
- Native to eastern North America
- Family: Salamandridae
- Order: Urodela
- Conservation status: Least concern
Adult eastern newts reach 7 – 12.5 cm (2.8 – 5 in) in length. This species has three distinct life stages, between which their physical appearance and lifestyle differ greatly. During the larval phase, the skin is olive green and individuals possess external gills. The eft phase is characterized by bright orange-red skin and the development of lungs and strong legs. Lastly, in the adult phase, the skin is green-brown with red spots on the dorsum and a paler belly.
While eastern newt larvae are aquatic, the efts are terrestrial and can be found in wooded areas where they forage among moist leaf litter. Adults, however, return to aquatic environments and inhabit ponds, wetlands, or streams. Notophthalmus viridescens is considered threatened in Iowa and is found in just a handful of counties in the east of the state.
Eastern newts produce tetrodotoxin, which is a type of neurotoxin that makes them unpalatable to predators such as fish, frogs, and turtles. Interestingly, efts with more spots on their dorsum tend to produce greater amounts of tetrodotoxin.
5) Common mudpuppy (Necturus maculosus)
- Native to the eastern United States
- Family: Proteidae
- Order: Urodela
- Conservation status: Least concern
The common mudpuppy is neotenic, meaning that it retains juvenile features into adulthood. This salamander grows to lengths of 20 – 48 cm (7.9 – 1 ft 7 in) and is gray-brown across the dorsum with a paler belly. It may also display small dark brown spots, particularly on the underside. The tail is laterally compressed, and individuals have bushy external gills.
Necturus maculosus can be found in the eastern third of Iowa, and despite an overall conservation status of least concern, it is considered to be threatened within the state. Common threats include sedimentation and pollution, both of which have detrimental effects on the common mudpuppy’s aquatic habitat.
The gill size of this species varies depending on its environment: in warm, slower-moving rivers or lakes it develops larger gills, whereas in fast-flowing rivers and streams the gills are much smaller. Individuals often seek refuge underneath sunken rocks and logs.
Amazing creatures! Have you ever spotted a salamander in Iowa? We would love to hear your experiences!