Cane Toad
Rhinella marina

Cane Toad (Rhinella marina)
Taveuni, Fiji
I have had to correct this blog post.  Previously, this post was about the Cane Toad (Rhinella marina) discussed the Cane Toad as being a species native to Texas, Mexico, Central America, South America and introduced to a variety of places worldwide.  But a recent study based on mtDNA and skull morphology has shown that this "species" is actually two species of toad!  So I am changing this blog record to cover Rhinella marina and will make a new post for the Texas species, Rhinella horribilis.

The infamous Cane Toad (Rhinella marina) naturally occurs in tropical South America, east of the Andes.  (There is a sister species which occurs west of the Andes and north into Central and North America).  However, it is most famous for the fact that it now occurs all over the world due to its introduction to try and control pest insect species. It is now found on islands in the tropical Pacific (including Hawaii, Fiji, the Cook Islands, Marianas Islands, and many others), New Guinea, Australia, the Phillippines, many Caribbean and Antillean Islands, Florida, Bermuda, Japan, Taiwan and there are likely other areas still waiting to be documented*.  
Once they get established, their generalist habits make them easily adapt to the new environment.  These Cane Toad tadpoles were photographed in a stream right next to the ocean away from the tourist areas on the relatively isolated island of Taveuni, Fiji.

Cane Toad tadpoles
Taveuni, Fiji
The problem is that although the species was introduced as a pest control method, they have become pests themselves in many of these areas.  It is a large toad with a large appetite and will eat anything it can swallow.  It has significantly impacted the local amphibian populations in some areas simply by eating and outcompeting the native frogs and toads. 

Furthermore, for larger animals it presents a problem because it is highly toxic.  It's skin, particularly its massive parotoid glands behind the eye and on the shoulder, produce a toxic sticky secretion.  In some areas where it is introduced (e.g. Australia), native animals have no experience with or resistance to its poisonous skin secretions and eat the toads then die.  They have also killed many domestic pets through poisoning.

But, it does have a place in the world.  In its native range there are controls to its population that have evolved along with it.  It isn't the Cane Toad's fault it is a problem, it is the fault of the men who transported it from its native range.

These are massive toads. Adults have exceeded 5 pounds in mass and been over 15 inches long.

The call of the Cane Toad is actually what you would expect for a huge toad.  Toads generally have trilled calls.  Smaller toads have faster, high-pitched trills and big toads have slower, low-pitched trills.  The bigger the toad the lower pitched the trill.  

Here's a call from an individual the Daintree National Park in northern Queensland, Australia.

Cane Toad call from Daintree National Park, Australia

© Chris Harrison 2014

* one of the difficulties presented by the new split of the Cane Toad (R. marina) from the Giant Toad (R. horribilis) will be sorting out exactly which species is introduced around the world.  At the moment, the data suggest all the introduced "Cane" Toads are Rhinella marina.

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