Module 22 – Cane Toads in Australia

Transcript of Module 22 – Cane Toads in Australia

Today’s Aussie fact I thought I would talk about cane toads (1), and I’m not sure if I’ve talked about these before or not, but maybe you guys have heard of (2) cane toads in Australia. If you go north, you will definitely see cane toads.

So, I recently saw a news article this week about the genome (3) having been cracked (4) for cane toads, meaning that the genome of the cane toad, the DNA sequences (5) of the entire DNA of the cane toad, has been successfully sequenced (6) now, and it got me thinking about the cane toad, and I thought I would go through a number of different facts about it. Okay? And there’ll be a link in the transcript for this article if you’re interested.

Alright, cane toads. So, cane toads are a type of frog (7) and they were introduced into Australia, they are an invasive species (8) in Australia. They are not natural. They aren’t endemic (9) here.

They’re about four to six inches long when they get to fully-grown (10) size and they can weigh up to about four pounds, so close to two kilos, which is pretty impressive (11) for a frog, and the females actually end up a lot larger than the males, and this may not come as a surprise (12), because females are, obviously, the animal that produces all the eggs. The males produce the sperm. The females produce the eggs. So, they’re egg producers (13) and layers (14).

Once fully grown, the females can deposit (15) up to 30,000 eggs in a single night. That’s crazy. And it only takes three days, 36 hours, for these eggs to hatch (16) into tiny tadpoles (17). This is obviously one of the reasons these guys are such successful invasive species. So, these tadpoles slowly grow their back and their front legs, usually the back first then the front, and they transform into (18) froglets (19), young frogs, after only four to eight weeks. They can live up to 10 or 15 years in the wild and up to 35 years in captivity (20). That’s four years older than me. Crazy!

Cane toads are highly poisonous (21), though, they’re very dangerous (22), and produce a toxin (23) in the glands (24) on the back of their neck so that if anyone picks them up or bites them, attacks them, often this toxin, when pressure is put on this gland, is released, it’s spat (25) out of the frog and it can kill really quickly. So, that’s why there’s such a danger to native (26) animals, especially animals that hunt them.

So, the cane toad isn’t native to Australia. We established (27) that at the start. And it was ignorantly (28) introduced into Australia in 1935, so 83 years ago, by a man named Reginald Mungomery (29). So, he brought these over to Australia in a flight (30) from Hawaii (31) where he picked up 102 of these cane toads, 51 males and 51 females. And this guy was supposedly trying to fix (32) the problem of cane beetles (33), cane grubs (34), that were destroying sugar cane (35) crops in northern Australia.

The problem was that the frogs can’t jump very high, right? So, the cane beetles (36) were at the top of the sugar cane (37), which can be metres high, and the frogs don’t get up that high.

So, these toads were initially released around Cairns (38), Gordonvale (39), and Innisfail (40) in Far North Queensland (41), and shortly after this ‘the march (42)’ of the cane toad began. And this is known as the ‘Invasion Front’ (43) in Australia. I remember this at school always being spoken about. Where the cane toads at now? Which cities or towns are they about to get to?

So, the march of the cane toad moved at about 10 kilometres a year until the 1960s when it significantly began to pick up pace (44), it began to speed up (45). By 1945, the cane toads had reached Brisbane (46), which was 1,600 kilometres south of where they were first released. They started knocking on the doors (47) of people in Byron Bay (48) in New South Wales (49) in 1965. And by 1984, they were stealing the cat food from unsuspecting (50) kitties in the Northern Territory (51). And in 2009, they finally marched across into Western Australia (52) on the far west of the continent (53).

So, until today, the cane toad is one of the most catastrophic (54) ecological disasters (55) to have ever happened in Australia, much worse than any other introduced species. Whether it’s rabbits (56) or foxes (57) or donkeys (58), the cane toad has been devastating.

Despite this, scientists are still hopeful (59) that they can fight against (60) the cane toad by coming up with unique ways to control cane toad numbers. Although we’ll never be able to completely eradicate (61) the cane toad, hopefully studies such as the one I mentioned at the start, where the genome has now been completely sequenced, will allow scientists to identify (62) weaknesses in the DNA of the cane toad or maybe in diseases that affect the cane toad, but don’t affect native animals, and they can use these to exploit (63) the cane toad and control their numbers in the future.

So, my question for you today is one: have you ever seen a cane toad in real life if you’ve been to Australia? And two: have you seen the awesome cane toad documentary Cane Toads: An Unnatural History (64)? So, I recommend checking out that doco (65). It is amazing. And it is full of Australian humour and you will learn a lot about… not just Australia and Australian culture, but also about the cane toad too if you check that out.