Science blog – BentMedia

How tame are animals that are not afraid?

Posted on March 31, 2013March 31, 2013 by BentMedia in Science blog

Grey leaf monkey checking out the pictures I took on its mates. I am the guy in the green shirt. Picture taken by Henrik Sjödin

During my recent trip to Asia, I visited a couple of places where animals never experience hunting. One of these was the Labuk Bay proboscis centre just outside Sandakan in Sabah, Borneo, created primarily for proboscis monkeys living in a remnant of forest surrounded by palm oil plantations. The proboscis monkeys are supplementary fed regularly at the centre, and at times even grey leaf monkeys visit the feeding areas. Some of the grey leaf monkeys accept vegetables, while other individuals seem to be less interested. However, all the grey leaf monkeys show very little fear of people, to the level where some of them interact freely with visitors. The young female in the picture above actually looked at the pictures I showed her on the screen of my camera. The proboscis monkeys also show an amazing lack of fear, with certain dominant males ignoring people irrespective of distance.

Proboscis monkey, allowing me to approach close enough to be able to take a wide-angle picture starting at its hand.

The second place I visited with no hunting or other persecution of animals was the Danum Valley field centre outside Lahad Datu, also in Sabah, Borneo. This research centre has been active for more than 25 years, with a total protection for all animals inside the protected area. Some animals live close to the field centre itself, and become incredibly accessible. One wild orangutan has totally lost her fear of people.

In Danum Valley, there is also a resident herd of Sambar deer. These deer are generally hunted outside protected areas, and are shy there. In the Danum area, all deer let visitors approach to around 15 metres, while some of the deer have become so tame, that they can be petted and hand fed.

Bearded pigs and other animals, such as longtailed macaques, some civets and tree shrews seem to very quickly loose their fear of man in protected areas.

So, what is my point? Animals that are not shot at are less afraid! That is not a major revelation. But there is a consequence to the hunting and other activities that are not often discussed. As an avid animal watcher, I find most animals very hard to find, and even more so, really hard to actually follow and study. That is outside protected areas. Inside protected areas, many animals are very easily observed and do behave seemingly natural even in the presence of humans. On a scientific notion, such observations give a lot of information on the ecology of such animals. Furthermore, on a more societal notion, to many people including myself, it is a great experience seeing wild animals behave naturally in their environment. I wonder what a world without any hunting and other similar activities directed towards animals would be. It is easy to envision some kind of “Eden”like place where we could interact with animals in a much closer way than we do now. I would for one really like to try it.

Red leaf monkey, feeding next to my breakfast table

All animals portrayed in this entry are wild, are not restricted in movements in any way and are free to leave and go wherever they will. None of them are captive bred, and none have ever been in captivity. All allowed me within 5 meters distance, and some obviously even closer without any sign of stress.

Mind blowing parasite

Posted on March 25, 2013March 25, 2013 by BentMedia in Science blog

One can find really weird things when walking along a Southeast Asian rainforest path. Common examples are ants, and more rarely other insects or spiders, sitting under a leaf with weird club shaped appendages growing out of them. At closer inspection of the ants in question, it is clear that the ants have their mandibles firmly anchored in the leaf, and, furthermore, that the ants are quite dead. Almost always the arthropods showing such of appendages are positioned right under the leaf, often biting around the leaf stem, thus keeping as dry as possible in the rainy and humid environment of the rain forest.

What has happened to these poor animals? Well, the fungus Cordyceps, or close relatives to Cordyceps, has happened. Cordyceps is a genus of endoparasitic fungi which attack arthropods such as insects or spiders. The attack from the Cordyceps starts when a spore from the fungus gets attached to the outside of the arthropod and germinates. The mycelium of the fungus enters the insect or spider through its breathing apparatus, which consists of small tubes, so called trachea, that transverses the body of the animal (or in the case of spiders, book lungs, that from the perspective of the fungus serves the same function).

The fungus soon starts to grow inside the animal, reaching every corner of the still live animal, converting animal matter to fungus mycelia. After a while, when the fungus more or less have exhausted all non-vital parts of the infected animal, the fungus by chemical means takes control over the ”brain” of the arhtropod. The arthropod is ”told” to climb up in the foliage and attach itself to a leaf, where it sits well protected from the frequent rains. Here the Cordyceps finally kills of its victim, converting the last matter left from insect or spider to fungus. Then the fruiting bodies, the appendages, grow out of the victim, and the fungus starts producing millions and yet millions of spores. Due to the positioning of the now dead victim, these spores are kept quite dry, and can thus spread over quite some distance in the hope of infecting yet another ant.

So is this a aquisition that the ants and other victims of the fungus havent yet had time to evolve a countermeasure to? It turns out that there are 48 000 000 years old remnants of bites of infected ants on fossil leaves. The bite marks are so characteristic that researchers are confident that Cordyceps have been taking over the minds of ants for at least so long. It is somewhat surprising that the ants haven´t been able to adapt to the fungus and evade the quite gruesome effects of getting infected.

Interestingly, some Cordyceps species are considered to have medical effects and have been used in traditional Tibetan medicine as an aphrodisiac. It is quite clear that the Cordyceps fungi group contain biological active chemicals, and some of those are being studied for use in modern medicine. Wouldn´t it be incredibly cool if a 48 000 000 year old chemical used to take over the mind of ants and other arthropods could be used to cure some of our modern day ailments?

Fluorescence and bioluminescence

Posted on January 22, 2013January 22, 2013 by BentMedia in Science blog, Uncategorized

When I arrived in Lembeh 2013 it was just after Christmas. However, I was up for another Christmas event. Simon, my host from NAD had ordered a bunch of cool stuff for me from Sola. A Night sea lamp, strobe filters, filters for the lens and a cool pair of yellow spectacles for the spectator waited for me here. I have now tried this system during a number of dives and will in this blog give a short overview over what I learnt from shooting it. But first of all I want to give a brief explanation over what fluorescence is, and why we can find it in nature.

First of all, fluorescence is often confused with bioluminescence. Bioluminescence is found in more and more animals, and in a number of mushrooms as well. Well-known examples are those of plankton giving of light when disturbed, deep-water organisms with light organs, mushrooms glowing in the forests, fire flies and for northern areas glowworms. Bioluminescence is the emitting of light involving a chemical reaction. Very generally, the light emitting substance is a protein called luciferin, which emits light through a chemical reaction catalyzed and oxidized by an enzyme, called luciferase. Thus, a chemical provides the energy fueling bioluminescence, using oxygen in the process.

Fluorescence, in contrast, is the emission of light where energy from one (or on rare occasions two) photon excites an electron into a higher energy orbital. After a short time, the electron will return to its former level, emitting the excess energy as light of another wavelength. No oxygen will be used in this process, as the light emittance is fuelled by the energy in the photon. Many different subjects in nature fluoresce. Despite that, we can seldom see the fluorescence, as the emitted light level is low, or in wavelengths we cannot detect. One notable exception is the red or orange anemones that we sometimes can se in much deeper water than red and orange colors from sunlight penetrate water. Despite being fairly poorly understood on a biological level, fluorescence is used in many applications, from mineralogy, oil detection, microbiology and forensic work.

So why do things bioluminesce or fluoresce? Bioluminescence in marine systems is used for at least three widely different purposes. Most of the deep-sea bioluminescence seems to be used in order to attract prey. Second, a number of fish living in the zone deep enough for a little light to get through, use bioluminescence to counter shade the ventral side of them, so shading against the faint surface light can not be used by predators to find prey. Third, and maybe most speculative, it is thought that small crustaceans that bioluminesce do so to deter small predators. Why would small predators be afraid of light? Well, if a small more or less translucent predator eats a bioluminescing crustacean, the small predator will light up and attract the next step upwards in the food chain, increasing small predators risk risk of being killed them selves.

What is the point of fluorescence in marine systems? For a number of shallow water cnidarians, mainly the ones using zooxanthellae for their energy input, fluorescence has been suggested to be a way to control excess levels of sun exposure, limiting the damaging effects of uv-light. Both proteins in the coral itself as well as chlorophyll in the zooxanthellae associated with the coral may fluoresce. The available evidence, however, does not really support this theory.

A number of other animals fluoresce. Some crustaceans, such as the anemone hermit crab fluoresce. Also some bristle-worms, fish and cephalopods fluoresce.

There seems to be no reason for these animals to fluoresce, so much fluorescence simply seems to be a side effect of other processes in living creatures. Whatever the cause of fluorescence it really is quite magical to see the different sources of fluorescence light up leaving the rest of the surroundings pitch black when diving. Try it out, it is an experience I am sure you will not forget!