( ALGS )


Snakes and Lizards

May 2009


The Thursday talk for May was a slide presentation entitled “Snakes and Lizards” by Nick Bessant where he went through a number of slides from his vast collection talking in detail about the evolution of lizards and snakes. He started showing various tortoises which are in the same family and is a lizard but with a soft body that needs the protection of a hard shell. He then progressed to the lizards pointing out not only the obvious differences between the lizards and snakes but also the family links for example the snake still has the remains of its hind legs in the form of a small claw towards the tail. Lizards have ear slits with an acute sense of hearing but no eyelids and the eyes are always open, and the Geckos which are nocturnal insect eaters have very large eyes.

Whereas snakes have eyes that are protected and do not have any ear slits, relying on sensing vibration though it body to warn of danger of food nearby. The Grass snake is actual a legless lizard.

The snake’s skeleton is made up of 300 vertebras and the ribs are only connected to the backbone which allows the body to greatly expand to accommodate it prey. The teeth are angled backed to help it swallow its prey whole. Snakes fall in to two categories when it comes to eating, there are the poisonous verities that inject there prey with venom to subdue them and help with digestion, and the constrictors who kill there prey by crushing.

Both Lizards and snakes have developed various methods of evading capture or escaping when threatened ranging from camouflage to, in the case of lizards, the ability to break off part of its tail if caught then re-grow it.



Nick brought along a number of live exhibits to thrill the audience these including lizards, a corn snake, a milk snake, male and female Indian sand snakes (the female is 10 times the size of the male), a Brazilian rainbow snake and a Royal Python. The exhibits were in traveling cages kept inside black bags and when he introduced them one at a time from their traveling boxes and the colours were brilliant. Members of audience later had the opportunity to hold the Royal Python and a number of the ladies and youngsters did just that.