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Habitat – nearly every temperate habitat, from rainforest to savannah, farmland to suburbia

Niche – large opportunistic predator

Favorite Food – insects

Length – up to 9 inches

Status – common

Invasive Species

The marine toad is the largest toad on Earth by far, growing as big as 9 inches in length. They are insatiable hunters, prowling their territories by night and gobbling up anything that can fit in their mouths. In addition to their staple diet of insects, they will scarf down unlucky salamanders and even small frogs. As if their massive size wasn’t enough to deter predators, marine toads also sport a deadly defense mechanism. If an animal picks up the toad in its jaws, special glands in the amphibian’s skin will ooze a highly toxic venom. The hapless predator scarcely has time to wish it never chose the toad as its last meal, as most are killed within 15 minutes of ingesting the poison.

In many regions of the world, especially Australia, the marine toad is an invasive species, competing with native frogs and toads for food and water. In certain cases, the introduction of marine toads was deliberate, particularly in countries that grow sugar cane. Since these toads are so voracious and are useful in pest control, they were thought to be effective watchdogs of sugar cane crops and earned the name cane toad. Although some farmers may have benefited from the introduction of cane toads, local ecosystems have been devastated. Marine toads are tough amphibians that can thrive in just about any environment on earth. Unlike frogs, they have thick, warty skin that allows them freedom from standing water except for mating. They are also tolerant to salt water, which amphibians usually shun, and can go without water entirely for long stretches of time. They are the ultimate survivors of the amphibian family, for better or for worse.

Because of their wide distribution, high tolerance, and high reproductive rate (over 20,000 eggs are laid in a clutch), marine toads are common and unlikely to be impacted by many of the same forces jeopardizing the survival of their frog and toad cousins. The marine toad is an example of how a hardy survivor can carve out its own niches in new areas, to the detriment of other species.

Habitat – varied: coastal woodlands, grasslands

Niche – small opportunistic predator

Favorite Food – insects

Length – up to 20 inches

Weight – a few pounds

Status – Common

Imagine you’re a small predator looking for a meal. After some time prowling the dusky landscape of northern Australia, you spy a sluggish lizard basking in the sun. You observe from a distance that it moves slowly and clumsily even in the heat of midday. Deciding that it will be your next meal, you move in. As you move within striking distance, something unexpected happens. All of a sudden, the reptile you took for an easy meals puffs up and opens its mouth wide, hissing as it flicks out a monstrous-looking blue tongue. You run.

At first glance, the blue tongued skink doesn’t seem like anything special. In fact, due to its coloration and sluggish nature, it’s often mistaken for a fallen tree branch in the coastal woodlands and interior grasslands of Australia where it lives. It’s a locally common reptile in Australia and feeds on a variety of insects, slugs, and snails, with the occasional berry or flower. It’s also been known to scavenge at picnic sites for tasty scraps left over from human visitors. Active by day, it will seek refuge under debris or inside logs as shelter from the cold night.

The blue tongued skink has a large triangular head, and a long, heavily-built body. It’s big for a skink, with adults measuring between 14 and 22 inches. But it’s not size that makes the blue tongued skink so special. As its name implies, it has a striking, blade-like blue tongue that the animal uses to frighten away threats. For most would-be predators, the mere sight of bright blue is enough to deter an attack. In the animal kingdom, bright colors often signify that an animal is venomous, or at the very least, dangerous. However, behind all the bluster, the blue tongued skink is mostly harmless. If cornered, it can deliver a powerful bite to a person, but its tiny dull teeth are unlikely to break the skin. Like other skinks, its tail is one of its main defenses against predators. If its blue tongue fails to frighten away a carnivore and it manages to bite the skink’s tail, it will break off, allowing an escape. The tail will grow back in a matter of weeks.

Mating is serious business for the skinks and the males are territorial, defending their turf and prospective mates against other males. Courtship involves a brief chase and a love bite delivered by the male on the back of the female’s head. 150 days after mating, the female will give birth. Blue tongued skinks don’t lay eggs, but rather give birth to a litter of between 5 to 25 live young. If they’re fortunate enough to survive the trials of growing up in the forbidding Australian wilderness, they’ll reach maturity in about 3 years. Blue tongued skinks have relatively long lifespans and in captivity have reached 25 years of age.

Although behind its characteristic feature, the blue tongued skink might just seem like just another chunky lizard, it’s yet another striking example of the wild diversity of reptiles in Australia, and on planet earth.