Red Salamander

AmphibianUnited States

Aug 31

Written By Alexander Julius Jensen

Pseudotriton ruber

During mating season, male red salamanders are not aggressive towards each other. In fact, they actually court one another — this likely isn't a case of mistaken sex, but an attempt to trick rival males into wasting their sperm packets (spermatophores).

A Red Creature in the Night

A shiny, bright red creature wriggles out from beneath a moss-covered log. It hastens across the forest floor, slinking over and crawling beneath the leaf litter. The moon hangs in the sky, scattering pale light through gaps in the branches, creating a disorderly, shifting mosaic of light and dark beneath the trees. Before long, the creature reaches a cold, babbling stream, its waters meandering slowly through a winding bed — one of many streams birthed from the rolling peaks of the Appalachian Mountains. On a stone beside the stream, the red creature perches, letting water droplets speckle its body and trickle along its skin. Freed from tree cover, moonlight falls upon the creature's amphibious form.

It isn't large; probably not much longer than 15 cm (6 in). Its body is slender and cylindrical, with four stubby pairs of limbs splaying outwards from its sides. One end of it tapers to a short tail and the other to the creature's flattened head. Situated on either side of its head, above its black-fringed "lips", rest its protruding eyes, glowing golden, with dark bands over rounded pupils. Silvery, celestial light dances across the creature's skin, which glimmers with moisture. A bright orange-red, it appears like shining amber or a ruby, dappled with black dots all over.

The Lungless Salamander

This nocturnal creature is named, somewhat uninspiringly, the red salamander. It inhabits the cold streams and springs of the eastern United States, from New York in the north to Louisiana down south. It can sometimes be found hidden under logs and rocks, or beneath masses of leaf litter, but it rarely strays too far from water, and for good reason. This salamander, and amphibians in general, are very susceptible to desiccation — they dry out and die without access to moisture. This is because of their highly permeable skin, which loses moisture quickly via evaporation. While this seems like a liability, it also confers an advantage; amphibious skin can easily take in gases from the outside, essentially allowing amphibians to breathe through their skin (called 'cutaneous respiration'). Some, like the red salamander, take this to the extreme.¹

The red salamander is a plethodontid ², also known as a ‘lungless salamander’. That descriptor is quite literal; the red salamander does not have lungs. As such, it relies on cutaneous respiration, skin-breathing, to get oxygen into its bloodstream and expel carbon dioxide. Along the sides of its body, it has 16 or 17 vertical grooves — scarcely noticeable unless you're looking for them — each groove corresponding to a space between the salamander's ribs. These are called 'costal grooves' and they function to transport water over the surface of the body by providing grooves and channels through which it can run, helping to keep the salamander's skin moist and fit to respire effectively. In addition, these grooves also assist in temperature regulation (thermoregulation); quite useful for an ectothermic animal — one whose body temperature is largely determined by exchanging heat with its environment.

Tactile Flirting

For the red salamander, conserving heat can be vital, since winters in its northern range are far from balmy. As the weather becomes chill in autumn and frost grips the land in winter, the red salamander retreats to the bottoms of deep springs, where temperatures remain unchanged. Many of the females, however, are busy laying their eggs. They usually begin their depositing in the fall, flipping their bodies upside down and sidling under stream-side rocks to stick their clutches (of anywhere between 30 to 130 eggs) onto the undersides. For 2 to 3 months a female watches over her eggs, protecting them from predators. Once they hatch into tiny larvae, usually in the midst of winter, her duties are done and the young must fend for themselves. Depending on location, a red salamander's childhood (larval period) can last anywhere from 1.5 years in coastal regions where elevation is near sea level, to 3.5 years in the colder, higher regions of New York — the highest altitude that red salamanders live at is around 1,500 metres (4,920 ft).

But, before a female can lay her eggs, she must have them fertilised by a male (or several) and this is an entire, somewhat complicated, affair. The mating system of a red salamander is polygynandrous, simply meaning that both males and females have multiple mates. The male is the one to do the wooing; a prospect not made any less intimidating by the fact that females are the bigger sex. Red salamander courtship is decidedly tactile. A male begins courtship by putting his snout to that of the female, then uses it to caress her along the cheeks under her chin. If things appear to be going well, he begins to push his snout further beneath her head and then under her torso, squeezing himself beneath the female's body. If the female is charmed, she places her chin upon the base of his tail, with her legs to either side — presumably, if she is uninterested, the male must swiftly extract himself from his awkward position. But, if all goes well, the two amble about in this mounted position for a couple of minutes, until the male finally drops his sperm packet (called a 'spermatophore').

The fertile package having been dropped, the male directs his partner to the spot by raising his arched tail and waving it from side to side — like an excited dog, or perhaps like a traffic guard guiding her with a flag, for he doesn't stop his wagging until the female finds the spermatophore and picks it up. Having successfully delivered his sperm packet, and the female having successfully acquired one, they split ways. This is the ideal scenario, but in the competitive scene of salamander dating, those willing to lie and cheat often win the upper hand.

Sneaky Seduction

For species in which males compete with one another for females, their breeding season can often be a violent time. Elephant seals thrash each other bloody for the right to a harem; the skull-splitting battles of bighorn sheep echo through the mountains as they barrel into each other head first; siamese fighting fish, famous for their male-on-male violence, bite and chase one another; stags entangle their antlers in tense clashes and stag beetles use their impressive antler-like jaws to grab and toss each other. All for the hand (or hoof, or flipper, or fin) of the female. Male red salamanders do not compete with violence — they don't become more aggressive during their mating season, and there are no man-on-man battles — instead, it seems that they compete via sneaky, seductive tactics.

Just as a male will court a female, he too will court other males — with all the seductive rubbing that that entails. Tantalized by the other males' advances, the courted male drops his sperm packet. While we can't fully know the intentions of the seductive male salamanders, it isn't thought to be a case of mistaken sex (which can be identified through chemical cues), and the prevalence of the behaviour suggests an adaptive origin; the seductive male makes other males waste their sperm packets, thus giving himself less competition when he's actually courting females. But who's to say the males don't have a good time regardless?

¹ Other amphibians are even more specialised skin breathers. The Titicaca water frog lives in the depths of Lake Titicaca in the Andes mountains at elevations of 3,810 metres (12,500 feet). Its copious skin folds allow it to breathe — through cutaneous respiration — at such high altitudes. To increase gas exchange it spreads its limbs wide and pushes or hops up into the water column, breaking the boundary between the water and its skin as its skin-folds wave and ripple on the way down. It's also known as the "scrotum frog".

Clockwise from top left; imperial cave salamander (*Speleomantes imperialis*), Bell's false brook salamander (*Isthmura bellii*), arboreal minute salamander (*Thorius arboreus*), and Shasta salamander (*Hydromantes shastae*).

² Plethodontid salamanders are members of the family Plethodontidae. This group of "lungless salamanders" contains over 500 species, making it the largest family of salamanders. They are found mostly throughout the Americas, from British Columbia to Brazil — exceptions include a few species from Europe (European cave salamanders in the genus Speleomantes) and one in South Korea (Karsenia koreana or the Korean crevice salamander). Some live in streams, some in trees, others in caves or even underground.

This family also includes the only tropical group of salamanders. Plethodontidae contains some of the smallest living salamanders, with the arboreal minute salamander (Thorius arboreus) measuring some 17 mm (0.7 in) long, and some of the largest terrestrial salamanders, with Bell's false brook salamander (Isthmura bellii) measuring up to 36 cm (14 in) long. A subgroup, including European cave salamanders, can shoot their tongues from their mouths to catch prey — those in the genus Hydromantes, have tongues that project to 80% of their body length. Given the family is so large, such variety isn't surprising. The shared characteristic of all 500+ species: they all lack lungs.

**Where Does It Live?**

⛰️ Cold springs and streams, up to 1,500 metres (4,920 ft) in elevation.
📍 Eastern United States, from New York in the north to Louisiana down south.

‘Least Concern’ as of 10 February, 2021.

IUCN

Size // Small
Length // 10 - 18 centimeters (4 - 7 inches)
Weight // N/A
Activity: Nocturnal 🌙
Lifestyle: Solitary 👤
Lifespan: Up to 20 years (in captivity)
Diet: Carnivore
Favorite Food: Aquatic insects like water beetles, as well as earthworms 🐌
Class: Amphibia
Order: Urodela
Family: Plethodontidae
Genus: Pseudotriton
Species: P. ruber

The red salamander is known as a 'lungless salamander' (a plethodontid) and it indeed doesn't have any lungs. Instead, it breathes directly through its skin — an ability called 'cutaneous respiration'.
Along the sides of its body, it has 16–17 vertical grooves, each one corresponding to a space between the salamander's ribs. These are called 'costal grooves' and they function to transport water over the surface of the body by providing channels through which it can run, helping to keep the salamander's skin moist and fit to respire effectively.
The diet of a red salamander consists mostly of small invertebrates like insects, spiders, and worms. To catch them, it uses a projectile tongue that can extend and retract in milliseconds.
When threatened by a predator, this salamander will coil its body into a C-shaped defence posture. It also possesses glands that can produce a toxic secretion.
A male red salamander begins courting a female by rubbing his snout on hers. He then wriggles and squeezes his way beneath her body, until his head is beneath her tail and her head is on top of his tail. They walk around like this for a few minutes until the male drops his sperm packet (called a 'spermatophore').
He uses his tail to guide the female to the sperm packet — waving it in the air, from side to side, like a happy dog — until she picks it up.
In autumn, the female sticks her clutch of 30–130 eggs to the underside of a stream-side rock or log. She guards them for 2 to 3 months until they hatch, then they are on their own.
A red salamander's larval period can last anywhere from 1.5 years in coastal regions where elevation is near sea level, to 3.5 years in the colder, higher altitude regions of New York — the highest altitude that red salamanders live at is around 1,500 metres (4,920 ft).