Tag Archives: bangalore

Chameleons

As many as 180 species of chameleon camouflage themselves in varying habitats across the world. The evolutionary adaptations of this old world lizard is fascinating, a genuine testament to the millions of years Nature has invested on its spectacular design and functioning.

DISTRIBUTION: Found primarily on the mainland of sub-Saharan Africa, roughly 50% of all chameleon species exist in Madagascar. They are also native to southern Europe, north Africa, middle east, Sri Lanka, southern India and select islands of the western Indian Ocean.

As a favourite of the pet market, this gentle reptile has emerged as an invasive species in parts of the United States (Florida, Hawaii, California).

HABITAT: Chameleons are almost always found in warm habitats inhabiting every kind of tropical rainforest, savanna available; also seen in desert and steppe.

BIOLOGY: Best known for their ability to change colour, the chameleon’s locomotion is characterised by swaying gait. They have heavily ornamented faces (especially in males) sporting crests, horns, nasal protrusions or a distinctly shaped head. Their eyes are independently mobile but co-ordinate when focusing on prey. The upper and lower eyelids of a chameleon are fused with a tiny pinhole through which their retinas observe the world in 360 degrees.

Mostly arboreal, a prehensile tail enables them to cling onto wiry tree branches as tong-like limbs carry them forward in a manner so theatrical and distinct unto chameleons. A long, slender highly modified tongue is rolled up when not in use and launched to catch prey.

The very anatomy of the chameleon is adapted for climbing and visual hunting.

MASTER OF DISGUISE: Chameleons the world over are capable of varying combinations of colour as striking as turquoise, yellow or purple. This ability functions as camouflage, social signal and to regulate temperature observed in some cases. The darker colours are reserved for agitation or intimidation; males show multicoloured patterns during courtship. This amazing ability to change colour is employed by some, like the Smith’s dwarf chameleon, in accordance to the quality of vision of different predator species.

How do they do it?

Specialised cells called chromatophores contain colour pigments present in the cytoplasm three layers below a chameleon’s transparent outer skin. The first layer is yellow + red; second is blue or white and the third melanin, a dark pigment that controls how much light is reflected. The colour pigment in each layer rapidly distributes and re-distributes to influence the animal’s colour.

FEEDING: Insectivorous, ballistically project their muscular tongue to capture prey at a distance. A chameleon’s tongue to body ratio is 1 : 1.5 or 2 on an average and temperature heavily influences the amount of food it consumes.

More on the chameleon:

https://www.youtube.com/watch?v=H2ACbO6HEq8

The changing urban ecosystem

Despite the major advance in science and natural studies, humans are yet to comprehend the full range of impact they have on the environment. Human action are merely the first domino to fall and bring down along with it complex and intricate natural life cycles that have existed for billions of years.

Bangalore: A study of the rescue records from the last 25 years shows an explosion in the population of cobras, Russell’s vipers and rat snakes while non-venomous snakes such as green keelback, olive keelback (pictured below) are disappearing. Why?

The primary reason for this is our inefficient waste management system.

Scientifically speaking, snakes such as the cobra, Russell’s viper and rat snake have adapted well to the urban environment. The main reason for this is because of the endless supply of rodents hosted by the surplus garbage in the city. With most of our trash going straight into the gutter, the rodent population increases only to feed these expert rodent hunters better.

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Plump, well-fed cobra rescued from Bangalore city limits
The non venomous species on the other hand depend on amphibians (frogs, skinks, lizards, geckos) whose survival in turn depends on a healthy ecosystem which we no longer provide (due to degradation of resources, conflict in their allocation, climate change, urbanisation and many other factors).

Unchecked urbanisation is the reason why our co-inhabitants are dying out; the fact that we have eliminated so many species of snake from the checklist of Bangalore in such a short span of time is devastating.

From our archives: take a look at these non-venomous snakes that seem to be disappearing from the urban landscape:

Juvenile green keelback (Macropisthodon plumbicolor)
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Yellow collared wolf snake (Lycodon flavicollis) feeding on gecko
Olive keelback (Atretium schistosum)
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Dumeril’s black headed snake (Sibynophis subpunctatus)

List of non-venomous snakes whose numbers we have noted to be on the decline (going by total rescue calls received for each specimen since 2010):

Olive keelback

Green keelback

Buff striped keelback

Vine snake

Common sand boa

Banded racer

Kukris

Bronzebacks

Common wolf snake

Barred wolf snake