Docent Informations
What does "docent" mean?
We are a young group. The pioneers started the group in April 1997. Since then, we have grown modestly to 93 docents. The Night Safari Volunteer Rangers were brought under the Docent Programme in March 1999.
The docents are self-run by a committee of docents which co-ordinates inputs from all docents and liaises with the zoo management to put into motion the group's activities.
A docent newsletter is issued every two months so docents can keep up with the latest in zoo happenings and docent activities. Sprinkled with inspiring stories and amusing anecdotes, the Docent Deliberations is always a great read! We also constantly undertake research projects to expand and update our knowledge as well as explore new areas of interest.
Singapore Zoological Gardens Docents
WHERE ARE SNAKES FOUND?

Snakes are found almost everywhere! Mountains, deserts, in the sea, rivers, lakes, even in the Arctic.

Snakes have developed marvellous adaptations to a wide variety of habitats.

Are there places where there are no snakes?

No venomous snakes: New Zealand. Absolutely no snakes: Ireland, Antarctica


The most number of venomous snakes: Australia is the only place in the world where venomous species outnumber non-venomous ones, and where the most toxic snakes are found! 60% of Australian snake species are elapids and 25% of the world's elapids are found in Australia!

 

Semi-aquatic and aquatic snakes are found where the water is warm. Most snakes can swim, moving by undulating. But fully aquatic snakes have additional adaptations: paddle-like tails, flattened bodies; sand-papery skin to grasp slippery fish; valved nostrils and rostral groove (through which the tongue passes). All still breathe through lungs but can remain underwater for a long time. The lung, which may extend the length of the body, help it to float. Marine snakes (right) excrete excess salt through a gland in their mouth.

 

Burrowing Snakes: Only a few can truly dig out burrows, adaptations include: blunt noses protected by large tough scales or spade-shaped heads to dig with; a powerful tail, spined or armoured to push against in tight spaces; heads not differentiated from the body and fused head and scales to minimise friction. They scoop soil out with loops of their body. True burrowing snakes are found where the ground is warm. Most snakes can dig through loose soil to make a hidey hole or dig out prey. They do this by the concertina method to pile-drive into the soil. Snakes also happily use holes and burrows already dug out by other creatures or even share them with a current tenant: the Burmese Rock Python may share the burrow of a porcupine.

 

Desert snakes: Snakes conserve water well so they are ideal desert dwellers. Additional adaptations; being able to hibernate during hot dry periods, living off stored fat; move by sidewinding to keep off hot sand (left); underslung jaws and valved nostrils to keep out sand as they move; heavily ridged scales to move and burrow in loose sand. The Horned Viper (right) has horns above its eyes to protect it from the sun--serpent shades!

 

Some can concave their bellies to create an airspace to breathe in underground. Some stick just their eyes and noses out of the sand in ambush and wiggle their tail to lure prey within strike range (right). They usually stay underground during the heat of the day and become active only at dusk or night.

 

Tree dwellers: Arboreal snakes are either very long, thin and vine-like or shorter and stockier but with a prehensile tail. Vine-like snakes move quickly through the trees, and some can even glide: the "Flying" Snake (Chrysolopea) (left). Those with prehensile tails move more slowly, using their tails to grip branches as they move across space or lunge out for prey.

 

Arboreal snakes also have anti-skidding side scales and broad belly scales to grip smooth branches; and modifications in their heart and blood vessels so blood continues to flow even if they are vertical or their heart is lower than the rest of their body. Most are egg-laying as they need to keep their bodies light.

 

Most tree-dwellers rest in a typical flat coil draped over a branch with the head in the centre of the coil (right). Arboreal snakes have different height preferences. In most forests, some snakes prefer the top canopy, like the New Guinea/Green Tree Python (Chondrophython viridis), others the middle layers (like Green Mambas), and yet others the lower branches and bushes (these are semi-arboreal).

 

Cool Snakes: Snakes are found even up in the Arctic Circle and in high mountains. The European Adder (Vipera berus) is actually found within the Arctic itself in Siberia. Adaptations to the cold include: dark coloured (to absorb sunlight); give birth to live young; hibernate during winter, living off body fat. Snakes which have not built up enough reserves may starve to death during this time. One study suggests as many as 40% of hibernating Water Snakes (Nerodia sipedon) may not make it to springtime.

 

Some snakes hibernate in large groups at the same place every year, travelling long distances to go back to such a spot. This is common at high altitudes. Although huddling together helps slow down heat loss, eventually, all the snakes cool to the surrounding temperature because they don’t generate their own heat. They probably group because there are few suitable hibernation dens that never goes below freezing, is humid and predator-proof. Sometimes, good dens are so scarce that a wide variety of animals hibernate in the same spot. In Finland, one spot had toads, frogs, slow worms, lizards, grass snakes, bats and adders all snuggling together! Grouping together also helps these snakes to quickly find a mate. Such snakes usually mate before they go into hibernation or as soon as they emerge.

 

Another problem for cool snakes is producing young: European Adder (Vipera berus) females give birth to live young in about 2 months but don't feed while they are pregnant. Many die after giving birth and survivors often fail to gather enough energy to breed again the next season. So they breed infrequently. The Common Grass Snake (Natrix natrix) of Europe is an egg-layer that lives in temperate climates. Its eggs survive the cool climate because females travel long distances to find suitable laying sites, in particular piles of cow manure which generate heat as they decompose. The babies hatch before the first frost of winter.


More about snakes


- What are snakes?
- Are snakes cold?
- Why are snakes long?

- What do snakes eat? Do they drink?
- How do snakes swallow?
- How do snakes hunt?
- Why and how do snakes kill?

 

Snake predators and how do snakes protect themselves?
Snake mating, eggs and babies

 

Where are snakes found?
Fascinating snake adaptations to various habitats

Snake bites and first aid

Snakes in danger: role and conservation and snakes in human culture

Snake records: biggest, smallest, deadliest and more

 

- More snakes
- More animals
- General snake links and references



Further informations in german can be found here!

Further Links
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