How to make food come straight to you – Puff adder snakes show the way
Shaun Smillie | 2017-02-01 10:07:39.0
Dr Xavier Glaudas
Image by: Wits university
A flick of a tongue and all is not what it seems. Just north of Pretoria‚ scientists have discovered that puff adders are using their tongues and tails to lure amphibians close enough‚ so they can strike.
Like a wriggling worm on a fishing hook‚ the idea is to entice the amphibian with a perceived tasty morsel.
Dr Xavier Glaudas‚ a herpetologist at the Alexander Herpetology Laboratory at the University of the Witwatersrand‚ discovered this after analysing thousands of hours of film of puff adders hunting in the wild.
“We noticed that the snakes were extending their tongues for a long time‚” said Glaudas. “On average‚ if it was smelling the air‚ it would extend its tongue for about half a second‚ now they were extending their tongues on average of 8 seconds.”
In the animal kingdom this hunting technique is known as lingual luring‚ and it is used by some species of aquatic snakes‚ terrapins and birds like egrets. But lingual luring hasn’t been noticed amongst terrestrial snakes.
“We have seen in the footage frogs about to hop away‚ then turn 90 degrees and jump straight for the snake’s head‚” said Professor Graham Alexander‚ who was part of the study.
Glaudas spent three and half years following and filming 86 puff adders at a site in the Dinokeng Game Reserve‚ in Limpopo.
To track the reptiles‚ Glaudas first had to catch the snakes surgically‚ implant radio transmitters in them‚ and re-release them.
Using the radio transmitter‚ Glaudas would relocate his snakes while they were lying in ambush.
“We placed our cameras mounted on a tripod about 70cm away from the snake‚ and the camera continuously recorded what was going on. We came back the next morning to get the memory cards and reviewed everything that happened during the night‚” said Glaudas.
To strike at its prey‚ a puff adder needs to get to within one or two head lengths from its quarry.
The researchers have found that the snakes only use lingual luring to attract amphibian prey. This suggests that puff adders can distinguish between amphibian prey and small mammals.
But it is not just their tongues that puff adders are using.
Glaudas and Alexander have also noticed their subjects wiggling their tails‚ which they suspect they are also using to lure their prey. The only problem is that every time they have noticed this‚ the prey was not in screen.
Now the researchers want to know if lingual luring is just a puff adder trait or if it is used by other snakes.
– TMG Digital/The Times