2 Snakes That Are Invasive in Victoria

Invasive animals cause unmitigated damage to habitats worldwide — and it does not matter how cute the animal is! European rabbits in Australia, Burmese pythons in Florida, and Cane toads in dozens of locations outside of their normal habitat.

Australia has more than its fair share of deadly animals and snakes top the list. However, even though most of their invasive species are something other than snakes, there are a couple of invasive snake species that threaten to upend the delicate balance in the land down under. 

Corn Snake (Pantherophis guttatus)

Although they are beautiful pet snakes, corn snakes are not native to Victoria, or anywhere in Australia. They are a type of rat snake native to the southeastern United States. Like other rat snakes, corn snakes are nonvenomous colubrids. These snakes are exceptional climbers and can slither through the trees just as easily as they can along the ground. 

Corn snakes love eating small rodents. They also eat baby birds and other small prey — they don’t eat many reptiles but pretty much anything they can fit in their mouths will do.

These snakes can grow to about six feet long and have reddish-brown blotches on their backs with an orange or brown base color. They also have patterned bellies, reminiscent of maize. However, there are multiple color morphs, including albino and other less common genetic traits in those possibly wandering around Victoria. 

No one is certain how the species landed in Australia, but the most likely reason is they were originally escaped or released pets. As of today, officials are not certain whether corn snakes are fully established in Victoria. However, the state’s government includes it in a list of “pest animals” that need to be removed from the habitat.

The environmental damage corn snakes may do to habitats in and around Victoria is unclear. However, since they are active snakes that eat more frequently than some species, scientists speculate that an established population could outcompete some native species.

Boa Constrictor (Boa constrictor)

You may know the snake from the poem by Shel Silverstein, “Boa Constrictor,” but these snakes are well-known in the pet trade. Boas are terrific pet snakes that average 10 feet long but can grow to around 15. Their patterns make them popular — brown to red oval saddle markings that become deep read near the tail over a lighter base color. 

Boas are native to Central and South America, making them another non-native species in Victoria. As with corn snakes, boa constrictors likely originated as escaped or released pets. Younger boas are semi-arboreal and are often in the trees, all boas are capable swimmers.

Although mild-mannered as pets, these snakes are formidable predators in the wild. They eat everything from small rodents to animals the size of fully-grown rabbits. Boas are also active hunters, although they also take advantage of their excellent camouflage to wait for a meal to wander close enough. 

Of all the non-native reptiles seized by Victorian authorities, boa constrictors are the most common. These snakes have been spotted in Australia since 1999 and may have a breeding population. But since snakes are notoriously difficult to count in the wild, experts are not certain how many are currently in Victoria.

Because of their size, they may be able to take prey ordinarily eaten by native snakes like scrub pythons, competing for the same resources. Some experts believe invasive species can also spread diseases against which the native animals do not have immunity.

Other Invasive Animals in Victoria

Corn snakes and boa constrictors are not the only invasive species plaguing areas of Victoria. Several species are established in Australia and cause millions of dollars in damage each year. Some species were deliberately introduced as ways to control pests that damage crops or to control other accidentally introduced animals. However, some were stowaways on ships and in cargo containers.

Cane Toad (Rhinella marinus)

This large toad species is native to Central and South America. Its skin is dry, leathery, and bumpy and varies in color; it can be light tan, reddish-orange, brown, or black. In Victoria, authorities find about six to eight per year.

However, the main threat they pose is the toxins they secrete from their skin — it is poisonous to most other animals and the toxin often kills would-be predators. Cane toads were introduced into many areas outside of their native habitat as natural pest control. However, they breed prolifically and have become threats to native wildlife in nearly every area where they were introduced.

Smooth Newt (Lissotriton vulgaris)

This species is native to Europe and some parts of Asia. It is usually around three to four inches long and is usually brown with a spotted ventral side that can be shades of orange or white.

Smooth newts are not as dangerous to the local wildlife as cane toads, but they still compete with native animals for much of the same prey. In 2011, scientists discovered a small, localized population of this species in southern Melbourne. They believe it was the result of released or escaped pets. 

Red Fox (Vulpes vulpes)

Red foxes are easily identified with their reddish coat and bushy tails. They breed easily and can live in a wide variety of habitats, including scrub, farmland, and forest. Foxes are extremely versatile and have little difficulty adapting to new habitats.

During the 1850s, red foxes were released, mostly around Melbourne, for fox hunts. These cute little canids spread quickly across a continent and have few natural predators. Within 20 years after their original release, the Australian government considered them a pest species. Red foxes are present in about 75% of Australia and take a wide variety of prey.

Feral Pigs (Sus scrofa)

Pigs are big, strong, and destructive. When they escape from yards and farms, they go feral; and the feral pigs present in Victoria are the descendants of escaped domestic pigs. 

Feral pigs dig and root around, disturbing any agricultural field they happen to waddle through and will eat nearly anything they can, although leafy greens are their preferred food. They are also dangerous. These animals aggressively defend their young and their territory. Many people and pets have been injured by feral pigs over the years.  

Damage Invasive Species Cause

It doesn’t matter whether the species was an accidental release or deliberate. When it lands in a favorable habitat and has enough of a cohort to begin breeding, that species often throws the local ecosystem out of balance. It begins competing with local wildlife for many of the same resources — habitat, food, and breeding locations. And that is if it does not have the toxins that cane toads possess. 

In areas like Australia, which are home to some of the most unique plant and animal life in the world, invasive animals threaten native populations. These animals often have little to no defense against the invaders and fall prey to introduced diseases, toxins, and the challenges associated with reduced food sources.

The photo featured at the top of this post is © Jan Hejda/Shutterstock.com