Cane toads: (Bufo marinus) Were introduced into Australia to compete with the sugar cane beetle in 1935 (of which i think there are around 20 different species) from Hawaii/ native to South America it was an absolute disaster as Cane toads are not arboreal (tree dwellers) where the sugar cane beetle spent most of its time feeding on the new succulent shoots above ground the only feed the cane toads got were from the ones that lost their footing and ended up on the ground or the sick and dieing,
It gives you some idea just how much research went into the whole mess in to use them as a biological means of control is nothing short of a joke, there was a bit of a scare up in Darwin in the early 70’s when a supply of Cane toads were transported to one of the local Schools for dissecting in Biology class 4 or 5 of them escaped into the environment causing a great panic fortunately they were eventually all captured.
The Cane toad is venomous and many years back part of the venom (Bufotoxin) was used to determine pregnancy in humans however it is no longer used as synthetic alternatives have been developed. The Cane toad’s venom is also used for its hallucinogenic properties by licking the toad or drying the skin and smoking it (don’t try it) I think to be caught with dried skins on you is an arrest able offence as I think in some states of Australia the skins are actually on the controlled substances list but don’t quote me on that.
Description: The Cane toad can grow to an enormous size and eats pretty much anything they are quite fond of dog and cat food and have been observed eating baby chickens and mice, their coloration varies from dark to light brown to green and the skin is wart like in texture, they can reach sizes of around 230mm but are usually around the 100mm mark and are easily recognised from our native species by the large Paratoid glands either side of the head these are the venom glands that secrete Bufotoxin Cane toads can squirt this venom up to a meter in distance with a fair degree of accuracy, although not fatal to humans they can cause a great deal of pain if the victim is hit in the eyes.
Species impact: Since the introduction of this pest there has been a significant decline in reptile numbers especially the Python species pretty much anything that consumes the cane toad including Death adders, Taipans, and Browns are as good as dead except two species of snake one being the Keelback (Styporhynchus mairii) for sure, I also come across a dead Slaty grey snake (Stegonotus cucullatus) road kill, it was pretty mangled but I found seven small Cane toads in its gut so whether the Slaty grey has some sort of immunity to Bufotoxin I cant say, also whether the small toad-lets are toxic enough to kill the Slaty grey? Did it die from eating the small Cane toads or had it just been simply run over?
The Toad has not only taken a great toll on the Reptilian life here in Australia bird, mammalian, pretty much everything that consumes it ends up either very crook or dead! Crows have worked out a way around it by pulling the toads innards out through the mouth and the Magpie usually goes in through the soft underbelly to remove the innards this area contains no toxins.
Apart from its toxicity the Cane toad is a pest in other areas by way of wiping out large numbers of dung beetles that were introduced to Australia to deal with the huge amount of cow pats produced by the huge number of cattle we have here in Australia, the dung beetle breaks down these cattle pats returning it to the soil and improving soil fertility, they are an easily caught snack for the toad eating 80- 100 in a single sitting, The Cane toad is also an excellent host for several parasites them being the hookworm and roundworm.
What makes this pest so resilient and successful is they seem to have the ability to sustain serious injury and still function to a certain degree they are able to live in a series of habitats even saline water, they breed prolifically and native frogs stand no chance of populating against the Cane toad, the Cane toad can lay anywhere between 30- 35.000 eggs in a single spawn with a gestation period of between 48- 72 hours, our native frogs haven’t a hope in hell of competing with them figures, not only that the young Toads will feed on native tadpoles they also foul up the water.
The Cane toad (male) has the ability to undergo a complete sex change into a fertile female this gives them an advantage once again when populating new areas when there is a shortage of fertile females, also the sex drive in Cane toads is very strong they have been observed in full am-plexus with dead flattened toads on the road!
Distribution: Since the Cane toads introduction it has spread far and wide and has now reached the Arnhem land wetlands in the Northern territory where it is taking a toll on aquatic birds and even crocodiles, still there is no sure fire method of eradicating this pest period! So it looks like Australia for the time being is stuck with what I think next to the rabbit the worse thing we could of ever brought to this country.
Above: Cane toad with bufotoxin oozing from the Parotid glands
