Keelbacks in the Shallows

As I was showing my brother David the growth in the vegetation in our newest wetland system he pointed to some ripples coming across the water and we wondered if it might be a snake.  The source of the ripples was just out of sight so we both stood quietly watching the movement coming closer  until we could see not just one Keelback (Tropidonophis mairii) but two!  They were hunting independently but occasionally came close together as if comparing notes, only to separate again.  It was fascinating to watch the snakes from the height of our ‘lookout knoll’  as they swam, with graceful purpose, in search of prey constantly sensing the air with their tongues.  We are always happy to see these snakes at home in our wetland areas, they feed on frogs, lizards, tadpoles and small fish and are also able to consume small cane toads (Bufo marinus) without any apparent ill effect.  According to Steve Wilson (A Field Guide to Reptiles of Qld) this tolerance is probably inherited from related overseas species and genera that commonly eat toads.

While we have a cane toad control program at Wild Wings & Swampy Things which involves regular nocturnal excursions with the two of us armed with spotlights and collecting bags it is good to see that some native species are learning to cope with the toxicityof the toads.   We do see evidence of Water rats (Hydromys chrysogaster) having consumed most of the stomach contents of quite large toads which they have flipped over in order to avoid the parotoid glands, behind the head, which produce the poison.

4 responses to “Keelbacks in the Shallows

  1. Do you get the orangey coloured Keelbacks, or mainly the various greys? Re tipping toads to eat safely: I think this is as much luck as consciousness of poison. Any predator seeking to chew on a toad will go in through the soft belly and not the tough skin on the back. Snakes are a different case, because they must swallow the whole toxic package. It seems to follow that evolution shaped toads to defend themselves against snakes. None of which comes to much comfort to the vast array of naive Australian predators done to death by Bufo marinus.

  2. Haven’t seen any orangey coloured Keelbacks here Tony, mostly yellow tones with a greyish head.
    Re tipping toads – you may be correct in some cases but we are convinced that water rats have developed a method to avoid the toxins. Our evidence is the freshly killed toad carcasses, with little remaining on the skins, which have been rinsed in our bird baths and our natural swimming pool.

  3. Just catching up with your recent posts. You have been busy.
    Loved to see the Golden Shouldered Parrot.
    Great butterfly shots and interesting report of the Keelbacks.
    Its a whole other world up your way.
    Thanks for sharing.
    Denis

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