Pacific Giant Salamander Facts: They Secrete Toxin through Their Skin

Beneath the lush canopies of the Pacific Northwest, an extraordinary creature dwells, the Pacific giant salamander. With its remarkable features and intriguing adaptations, this amphibious wonder has fascinated researchers for years. Join us as we uncover the interesting facts about this remarkable aquatic marvel.

1. There’re 4 Pacific giant salamander species

The Pacific giant salamanders are characterized by their substantial size, sturdy build, and prominent features such as a massive head, well-developed eyes, and large limbs. Their relatively short tails are laterally compressed and exhibit a distinctive keel.

There are 4 types of Pacific giant salamanders, including coastal giant salamanders (D. tenebrosus), Idaho giant salamanders (D. aterrimus), California giant salamanders (D. ensatus), and cope’s giant salamanders (D. copei).

– The Idaho giant salamander possesses a striking appearance characterized by its intricately patterned and dark skin, which can display hues of grey, brown, tan, purple, or copper-like tones. They look like the tiger salamander in terms of shape and size.

– The coastal giant salamander, on the other hand, can grow to impressive lengths, reaching a minimum total length of 13 inches (34 centimeters). These salamanders exhibit varying color patterns, particularly during the metamorphosis phase.

Larvae generally display a dark brown to black base color, but as they undergo metamorphosis, their hue transforms into a silvery or dull golden shade. This transition results in a marbling effect that can vary from fine to coarse.

– The California giant salamander has a size between 6 to 12 inches (15 to 30.5 cm) in length. It displays a variety of colors, ranging from tan to dark brown to dull red. The limbs and dorsal surface of adult specimens display a mix of dark brown and purple patterns, while their underside is yellow or whitish.

– The cope’s giant salamander has medium size, with the adult size being about 7.5 inches (19 cm). They display a captivating coloration that combines marbled tones of gold and brown. Their snouts are rounded, their costal grooves are indistinct, and their tails are laterally compressed. It is quite uncommon to come across their metamorphosis, as most individuals are typically found in the larval phase.

2. Diet

Pacific giant salamanders, in both their larval and adult stages, exhibit predatory behavior and possess a wide-ranging diet. The larvae are notorious for their ability to eat nearly anything within their proximity, including insects, amphipods, snakes, crayfish, ostracods, mollusks, termites, and small fish.

Adult salamanders have a diverse diet, consisting of aquatic organisms and terrestrial prey. These include land snails, caddisfly larvae, slugs like banana slugs, spiders, moths, beetles, and flies. Interestingly, they even consume small tadpoles of their own species, other amphibians like snakes, as well as small mammals like shrews and white-footed mice. Apart from animal-based meals, the Idaho giant salamander also incorporates plant matter into its diet, such as small branches.

Their food preferences are influenced by their size and life stage. Smaller individuals tend to target smaller prey, while larger ones may consume larger prey items.

During rainy nights, they come out from their hiding spots and venture onto the forest floor to get food. They sometimes climb up to one and a half to two meters on tree trunks. These Pacific giant salamanders use the ambush strategy. They patiently wait for their targets and swiftly pounce short distances to catch them.

Pacific giant salamanders have quite a few predators, such as weasels, garter snakes, river otters, freshwater fish, salmonids, water shrews, and other salamanders of the same species. Furthermore, they are vulnerable to the parasitic chytrid fungus.

To protect themselves from predators, these salamanders possess slimy skin that hinders predators’ grip. Additionally, their skin secretes a poisonous substance, serving as an extra deterrent. They also produce barking or squawking sounds as a warning sign, head-but, and can bite the threats. Certain species of Pacific giant salamanders have camouflage adaptations suited for both their land-based and water-based environments.

3. Habitat

The Pacific giant salamander family has a restricted range mainly in the Pacific Northwest area of North America. The California giant salamander, for instance, can be located along the West Coast, its range in British Columbia is extremely small. These salamanders dwell in diverse aquatic environments, including streams, lakes, rivers, and ponds. They exhibit a preference for swiftly flowing water and seek out areas with sufficient hiding spots for protection and incubation of their eggs.

– The native range of the Idaho giant salamander includes northern Idaho and a small portion of western Montana. Additionally, a smaller population can be found in the southern region of Idaho near Warm Lake. These salamanders primarily inhabit forests in northern Idaho and western Montana, particularly in areas with small streams and marshy habitats.

They stay beneath rocks and logs close to the rivers. On the other hand, their aquatic larvae can be found in streams located at elevations above 975 meters.

– The coastal giant salamander has the largest range map of the. It lives in the coastal regions of northern California, Oregon, Washington, and British Columbia, with a limited presence in the southwestern region of British Columbia.

These salamanders thrive in small to mid-sized streams. They also inhabit moist, riverside forests with specific stream bed characteristics, such as gravel or small boulders and minimal silt. During times of rain, the salamanders may take refuge beneath the forest litter for shelter. They can be observed across a wide range of elevations, from sea level up to 1830 meters.

– The cope’s giant salamanders inhabit the Pacific Northwest region, specifically the Cascade Mountains and the Olympic as well as the Willapa Hills in southern Washington. They like to stay in clear and cold mountain streams that flow through damp forests. They spend their days concealed beneath rocks in these streams. However, as evening approaches, they become more active and freely roam the stream bed.

4. They’re solitary creatures

Pacific giant salamanders are nocturnal creatures. They are primarily active at night and tend to be secretive, often concealing themselves during the daytime. However, the Idaho salamanders differ from the others in that they are active both during the day and at night.

While Pacific giant salamanders are typically solitary animals, they do gather during the breeding season. During this time, they engage in territorial behaviors and protect their burrows.

To prevent their skin from drying out and to avoid well-lit areas and direct sunlight, they have a preference for damp environments. When the temperatures become too harsh, they (both larvae and adults) will seek shelter. In winter, they reduce activities due to the cold weather.

The California giant salamander possesses the remarkable capability to both dig and climb with the aid of its hardened toes. These salamanders are quite aggressive, even with their fellow species. The Idaho species, on the other hand, demonstrates a non-aggressive nature and tends to withdraw when faced with a threat. However, they can bite painfully if being touched.

5. Life cycle

The reproduction of the Pacific giant salamanders remains incomplete. These salamanders engage in polygynandrous mating, wherein both males and females have multiple partners over their lifetimes. Mating among aquatic organisms occurs beneath logs or rocks underwater, while courtship activities are carried out during the period from spring to fall. However, their specific methods of courtship have not been determined yet.

After mating, the females carefully lay a variable number of eggs (ranging from 85 to 200) in concealed nests underground or underwater. They diligently safeguard their eggs for a period of 6 to 7 months, during which they don’t eat anything. This behavior is similar to the mother Pacific octopus. However, the salamanders don’t die after the eggs hatch like the octopus. This behavior just limits the females’ reproductive capacity to once every 2 years.

Once the eggs hatch, the larvae stay within the nest for an additional duration of 2 to 4 months. They possess a considerable amount of yolk in their abdomen, which sustains them and allows them to go without feeding for several weeks.

As larvae, they live entirely underwater, equipped with gills to breathe. As their larval stage is about to end, they face an important decision: undergo a metamorphosis into terrestrial salamanders or persist in their fully aquatic form, retaining their gills.

Once they reach adulthood as terrestrial salamanders, a significant portion of their lives transpires concealed beneath the shelter of logs, stones, or bark. They seek refuge in the streambed or on land, but during periods of substantial rainfall, they may venture out more freely.

The larval stage typically spans a minimum of 1 year, but it can potentially extend up to 4 years. In the cope’s giant salamander species, you can barely see their metamorphosis. It seldom undergoes a transition to its adult form on land and predominantly resides in aquatic surroundings throughout most of its lifespan (neoteny condition).

They achieve sexual maturity between the ages of 3 and 6 years, depending on the specific Pacific giant salamander species. Although the precise lifespan of the Pacific giant salamander remains uncertain, other comparable aquatic salamander species are recognized for their extended lifespans. Certain species have been observed to live up to 23 years.

6. Conservation status

These salamanders are listed as Least Concern on the IUCN Red List. However, Pacific giant salamanders are extremely vulnerable to water quality degradation and environmental pollutants, which is happening now. Human activities such as logging and other interventions can result in increased sedimentation and elevated stream temperatures, significantly diminishing the quality of salamander habitats.

References:

• https://www.encyclopedia.com
• https://animaldiversity.org/