Chameleons: Interesting Aboreal Reptiles

 

Chameleons do not necessarily change their colour depending on the surroundings. They actually change their colour due to a number of different factors, including their mood, changes in light or temperature, or the humidity of their environment. They often change color to warm up or cool down. Turning darker helps warm the animal because the dark colors absorb more heat.

Different chameleons will also have different colours. For instance, a dominant, attractive male will have brighter colours, and a submissive male may be dark brown and grey. Females will change their colours based on whether they want to accept or reject a suitor.

                    

                                                          Von Hohnel's Chameleon

So how exactly do chameleons change colors? The outer layer of their skin is see-through. Beneath that are layers of special cells filled with pigment. To display a new color, the brain sends a message for these cells to get bigger or smaller. As this happens, pigments from different cells are released, and they mix with each other to create new skin tones. For instance, yellow and blue pigment may mix to make the chameleon look green.

A chameleon’s eyes can see up to 360 degrees. Chameleons have eyes in the backs of their heads and can move their eyes separately, with each eye having a field of 180 degrees. This means they can see 360 degrees if they need to.

This is useful since they can see predators coming from behind them, giving them a chance to flee on time.

Chameleons can also see ultraviolet light, which is not visible to humans.

                                                         Eye of Flap-Necked Chameleon

Chameleons come in a lot of different shapes and sizes. The smallest chameleon is the same size as your thumbnail and the largest chameleon is as long as a house cat.

The largest chameleon by length is the Malagasy giant chameleon, also known as Oustalets’s Chameleon. Some members of this species have been measured at almost two feet. The Brookesia micra chameleon, also from Madagascar is the smallest chameleon in the world. They grow to a maximum of just under 3 cm.

Chameleons have extremely powerful tongues. Excluding their tail, some chameleons’ tongues can be twice the length of their body. Their tongues consist of both muscles and bones, and can bend round to grab their pray.

The tongues are extremely quick and powerful. A chameleon's tongue can accelerate from 0 to 100km per hour in one-hundredth of a second, which is twice as fast as the fastest car. The tongue can be shot at a speed of  up to 8,500 feet per second, grabbing their prey within fractions of a second, making it impossible to get away. 

                                                   Chameleon's extended tongue
 

Chameleons have five toes on each foot. Most chameleons are highly developed to traverse trunks and branches. They have five toes on each foot that are grouped together into bigger bunches, with the toes on the hind feet reversed. These feet allow chameleons to grip on to rough or narrow branches with ease, aided by the sharp claw on each toe.

Chameleons have prehensile tails. Their tails are highly adapted to gripping on to branches and allowing them arboreal locomotion. Chameleons’ tails are able to curl several times around a branch, helping them to balance and hold on.

Some male chameleons have horns and spikes. Not just for show, though, these bodily decorations are used when a male has to protect its territory from another chameleon, and some of the spikes can help them blend into their environment.

                                                               Jackson's Chameleon

Some chameleons give birth to live young of up to 30 babies at ago while others lay eggs.

Chameleon can live up to 10 years.

No chameleon is venomous.

African Banana Slug

With a top speed of only 16.5 cm per min or 10 meters per hour, slugs are among the slowest creatures on the planet. Like all gastropod, the African Banana slug has one lung, one foot, and no spine. It is about 5 cm long but can stretch up to about 15 cm. It is variable in color and patterning, being yellow, white, orange, or gray, with or without banding, and it has gray or yellow tentacles and a yellow or orange sole.

Slugs have four tentacles. A pair of upper tentacles, which is longer, protrude from the top of their heads and are optical. Tiny black dots, or “eyes,” at the ends of the tentacles detect light and movement. A pair of smaller, lower tentacles, protruding straight out in front of their “face” are able to feel and smell. If the slug loses a tentacle to a predator or accident, the tentacle grows back.

On top of the slug, behind the head, is the saddle-shaped mantle. A respiratory opening called a pneumostome is located on the right side of the mantle and is more visible when it is open. On the mantle also are the genital opening and anus. The part of a slug behind the mantle is called the 'tail'.

                                              Parts of the slug

The bottom side of a slug, which is flat, is called the 'foot'. A slug moves by rhythmic waves of muscular contraction on the underside of its foot. It simultaneously secretes a layer of mucus that it travels on, which helps prevent damage to the foot tissues. Slugs produce two types of mucus: one is thin and watery, and the other thick and sticky. While the heavy mucus spreads from front to back, the thin mucus spreads from the center of the foot to its margins. Additionally, slugs secrete a viscous mucus that covers their entire body. Additionally, the slime facilitates slug mobility while deterring predators.

The "slime trail" a slug leaves behind have some secondary effects: other slugs coming across a slime trail can recognize the slime trail as produced by one of the same species, which is useful in finding a mate.

Slugs are hermaphrodite. They possess both male and female sex organs simultaneously. They are able to mate with themselves and self-fertilize. They however like to court and mate with other individuals. When the encounter each other, they push out and entwine their overly sized penis from their openings on the side of their head, before exchanging sperms to fertilize each other’s eggs. Occasionally, the penis gets stuck inside the partner's body. To separate themselves one or both of the slugs chew off the other's or its own penis. Once the penis has been discarded, the slugs are still able to mate using only the female parts of the reproductive system. They lay clutches of about 30 eggs under leaves and soil, and leave the clutch once laid.

                                    Slugs mating

While snails have shells to help protect their skin from drying out, slugs must stay moist to stay alive. To avoid dehydration, they secrete a layer of mucus, or slime, which covers their bodies. This is why most slugs are active just after a rain because of the moist ground or during nighttime. In dry conditions, slugs insulate themselves in dirt and leaves until their environment becomes moist again.

They eat detritus (dead organic matter), including fallen leaves and plants, animal feces, moss, and mushroom spores. They also feed on a wide dead organic matter and a variety of vegetables, including flowers, cabbages and strawberries.

The slugs are essentially harmless to humans, but can be serious pests of agriculture and horticulture. They can destroy foliage faster than plants can grow, thus killing even fairly large plants. They also feed on fruits and vegetables prior to harvest, making holes in the crop.

Slug control methods useful in small gardens include beer traps, crushed eggshells and coffee grounds. Salt kills slugs by causing water to leave the body through osmosis but this is not used for agricultural control as soil salinity is detrimental to crops.

In few rare cases, humans have developed rat lungworm induced meningitis from eating raw slugs. Slugs and snails are the primary intermediate hosts of the Angiostrongylus cantonensis- induced meningitis, where the larvae develop until they are infectious. Live slugs that are accidentally eaten with improperly cleaned vegetables (such as cabbages and kales), or improperly cooked slugs, can act as a vector for a parasitic infection in humans.

Nairobi Fly, Kenya Fly, Narrow Bee Fly

It is neither a fly nor a bee but a rove beetle, distinguished by its short wing covers. This beetle does not bite or sting. It is however well known, and feared, for the burns or skin irritation that it causes on human skin.

 

The beetle has a corrosive ‘chemical’ known as pederin, which is contained in its haemolymph, the invertebrate equivalent of blood. Pederin is released when a beetle is unintentionally brushed against or crushed against flesh, leading to chemical burns on the skin. The production of pederin relies on the activities of a symbiotic bacteria that lives within the beetle.

Because of these burns, the Nairobi fly is sometimes referred to as a "dragon bug” or “acid-bug."

Adult beetles are predominantly black and red in colour, and measure about 1 cm in length. Their head, lower abdomen, and wing-covers are black, with the thorax and upper abdomen being red – enough warning.

The beetles live in moist habitats. Heavy rains provide the conditions for the Nairobi fly to thrive. The beetle lives in bushes surrounding houses, in which it hides during the day but at night it emerges attracted by fluorescent and incandescent lights and as a result, inadvertently come into contact with humans.

Severity of the skin irritation (dermatitis) depends on the affected individual, the dose of pederin and duration of contact. Mild cases result in a slight redness of the skin. Moderate cases will start itching which later develop blisters. More severe cases could happen if the toxin is more widespread over the body or the area becomes secondarily infected. Treatment involves washing the irritated area with cool soapy water.

Affected individuals may inadvertently transfer pederin to other areas of the body, such as the genitals, the face or eye. If the eye is affected, because of hand rubbing, it can cause conjunctivitis – also known as “Nairobi eye”.

 

The Nairobi fly should be blown or gently brushed off your skin if it does land there. It should not be squashed or crushed. Should the beetle fluids get into touch with your skin, wash the afflicted area with soap and water.

 

Despite its name, Nairobi fly is not only found in East Africa. It is found in most of tropical regions.