At some point in prehistory, an earlier caldera-forming eruption occurred, leaving as remnants Verlaten, Lang, Poolsche Hoed, and the base of Rakata. Later, at least two more cones (Perboewatan and Danan) formed and eventually joined with Rakata, forming the main island of Krakatoa . The dating of these events is currently unknown; the Sunda Strait was first mentioned by Arab sailors around 1100 AD.
The Javanese Book of Kings (Pustaka Raja) records that in the year 338 Saka (416 AD):
A thundering sound was heard from the mountain Batuwara [now called Pulosari, an extinct volcano in Bantam, the nearest to the Sunda Strait which was answered by a similar noise from Kapi, lying westward of the modern Bantam (Bantam is the westernmost province in Java, so this seems to indicate that Krakatoa is meant. A great glowing fire, which reached the sky, came out of the last-named mountain; the whole world was greatly shaken and violent thundering, accompanied by heavy rain and storms took place, badul islandbut not only did not this heavy rain extinguish the eruption of the fire of the mountain Kapi, but augmented the fire; the noise was fearful, at last the mountain Kapi with a tremendous roar burst into pieces and sank into the deepest of the earth. The water of the sea rose and inundated the land, the country to the east of the mountain Batuwara [now called Mount Gede, a volcano in Western Java], to the mountain Rajabasa [the most southerly volcano in Sumatra], was inundated by the sea; the inhabitants of the northern part of the Sunda country to the mountain Rajabasa were drowned and swept away with all property ... The water subsided but the land on which Kapi stood became sea, and Java and Sumatra were divided into two parts.
There is no geological evidence of a Krakatoa eruption of this size around that time; it may describe loss of land which previously joined Java to Sumatra across what is now the narrow east end of the Sunda Strait; or it may be a mistaken date, referring to an eruption in 535 AD, for which there is some corroborating historical evidence.
535 AD event
David Keys, Ken Wohletz, and others have postulated that a violent volcanic eruption, possibly of Krakatoa, in 535 may have been responsible for the global climate changes of 535-536. Keys explores what he believes to be the radical and far-ranging global effects of just such a putative 6th-century eruption in his book Catastrophe: An Investigation into the Origins of the Modern World. Additionally, in recent times, it has been argued that it was this eruption which created the islands of Verlaten, Lang, and the beginnings of Rakata all indicators of early Krakatoa's caldera's size. badul islandHowever, to date, little, if any, datable charcoal from that eruption has been found.
Thornton mentions that Krakatoa was known as "The Fire Mountain" during Java's Cailendra dynasty, with records of seven eruptive events between the 9th and 16th centuries. These have been tentatively dated as 850, 950, 1050, 1150, 1320, and 1530 (all AD/CE).
In February 1681, Johann Wilheim Vogel, a Dutch mining engineer at Salida, Sumatra (near Padang), on his way to Batavia (modern Jakarta) passed through the Sunda Strait. In his diary he wrote:
...I saw with amazement that the island of Cracketovv, on my first trip to Sumatra (June 1679) completely green and healthy with trees, lay completely burnt and barren in front of our eyes and that at four locations was throwing up large chunks of fire. And when I asked the ship's Captain when the aforementioned island had erupted, he told me that this had happened in May 1680 ... He showed me a piece of pumice as big as his fist.
Vogel spent several months in Batavia, returning to Sumatra in November 1681. On the same ship were several other Dutch travelers, including Elias Hesse, who would be called a travel writer nowadays. Hesse 's journal reports that on
the 19th (of November 168)] we again lifted anchor and proceeded first to the north of us to the island of Sleepzie ( Sebesi ), uninhabited, ...[here he tells of a legend about crying ghosts, which actually were orangutangs ], and then still north of the island of Cracatou, which erupted about a year ago and also is uninhabited. The rising smoke column of this island can be seen from miles away; we were with our ship very close to shore and we could see the trees sticking out high on the mountain, and which looked completely burned, but we could not see the fire itself.
Vogel returned to Amsterdam in 1688 and published the first edition of his journal in 1690.
These reports of an eruption in 1680-81 pose somewhat of a puzzle. These are the only two reports of an eruption that have been found to date, yet at the time, the Sunda Strait was one of the heaviest-traveled waterways in the world. Records for this time period are particularly detailed, because there was an intense effort to wipe out pirates that were preying on vessels in the Strait. Neither Vogel nor Hesse mention Krakatoa in any real detail in their other passings, and no other travelers at the time mention an eruption or evidence of one. (In November 1681, a pepper crop was being offered for sale.) Both Van den Berg and Verbeek conclude from this that Vogel must have exaggerated the extent of the eruption he saw. Even so, there must have been an eruption around this time, since in 1880, Verbeek investigated a fresh unweathered lava flow at the northern coast of Perboewatan, which could not have been more than a couple of centuries old.
Visit by HMS Discovery
In February 1780, the crews of HMS Resolution and HMS Discovery, on the way home after Captain James Cook's death in Hawaii, stopped for a few days on Krakatoa. They found two springs on the island, one fresh water and the other hot. They described the natives who then lived on the island as "friendly" and made several sketches. (In his journal, John Ledyard calls the island "Cocoterra".)
In 1620, the Dutch set up a naval station on the islands, and somewhat later, a shipyard was built. Sometime in the late 1600s, an attempt was made to establish a pepper plantation on Krakatoa, but generally, the islands were ignored by Dutch colonial authorities. In 1809, a penal colony was established at an unspecified location which was in operation for about a decade. By the 1880s, the islands were without permanent inhabitants; the nearest settlement was the nearby island of Sebesi (about 12 km away), with a population of about 3000.
Several surveys and charts were made, but mainly for the purpose of mariners, and the islands were little explored or studied. An 1854 map of the islands was used in an English chart, which shows some difference to a Dutch chart made in 1874. In July 1880, Rogier Verbeek made an official survey of the islands, but he was only allowed to spend a few hours there. He was able to collect samples from several places, and his investigation proved important in judging the geological impact of the 1883 eruption. wikipedia.org
Volcanic activity recommenced in May, 1883 and continued into August, the first eruptions appearing on the northern, Perbuatan volcano. The number of active vents increased on bothkrakatau explosion 1883 the northern volcanoes. On the 26 th and 27 th August series of cataclysmic explosions occurred which were heard 3500 miles away as far away as South Australia and Ceylon, was recorded as of the world's biggest explosion the force of 100.000 hydrogen bombs, They generated tsunamis (tidal wave) crashed ashore and devastated hundreds of town and village, reaching almost 10 miles inland in some places. The resulting killer waves at speed up to a 350 miles per hour and reached height of 135 feet that were registered even in the English Channel , 11.000 miles away and which in the Sunda - strait area were devastating, killing more than 36.000 people. That total volume of material ejected by the eruption is estimated at some 18 - 21 cubic kilometers, 30 km high into the atmosphere with an ash cloud circling the earth several times. Causing "blue suns" and "orange moons" Europe and North America . The amount of the sun's energy reaching the earth was reduced, and in the year or two that followed, annual average temperatures in the northern hemisphere were than usual.
In the aftermath of the explosion only about a third of Krakatau remained. The northern two thirds, including the volcanoes Perbutan and Danan and the northern half of the Rakata Volcano, were gone. In their place was a collapsed crater (caldera) 200m beneath the sea, covering an area of about 28 square kilometer. The remaining, southern part of Rakata was left as approximate half, cone with an almost perpendicular cliff from the summit (813 m) to the sea, providing a natural, geological section through the volcano. The other two islands, Sertung and Panjang, were enlarged considerably (Sertung doubled in size) by the glowing ash and pumice which smothered them to a depth of 30 meters. On Rakata, the south and west coasts were were extended almost a kilometer-seawards and the ash layer reached a thickness of 60 m in some areas, although probably much shallower on the steeper slopes. Weeks after the explosion, rain water turned into steam as it trickled into crevices and a even month later the surface was too hot for bare feet. It is believed that all life, plant and animal, was destroyed on the islands. Yet the three islands are now covered in forest, and over 200 species of higher plants and 36 species of land birds have been found on Rakata in the 1980s.
At some point in the distant past, Krakatau consisted of a single, large volcanic island. This island was destroyed in eruptions presumably of great violence, leaving three fragments of the original volcanic walls in a brokenbadul island ring, or caldera, around the edge of this original island. The three islands are now named Rakata, Sertung and Panjang. Subsequently, further eruptions began, building up the largest island (Rakata) back into the center of the caldera. As of 1883, the only previous recorded eruptions had come from this big island in 1680. The islands of Panjang and Sertung, then as now, remained dormant. Then in May of 1883, eruptions began again on the big island, and one by one, the three peaks of the island -- Perboewatan, Danan and Rakata -- each came into action as the cycle of building and destruction reached its peak. Finally, on August 27th, the sequence ended in catastrophe, as huge volumes of ejecta were hurled into the sky, plunging the surrounding region for a radius of 80 km into 57 hours of darkness. Relatively few people appear to have died as a direct result of the ejecta, but huge numbers died because of an indirect consequence of the eruption. As the magma chamber emptied, the outer walls of the volcano failed, and collapsed -- repeating the pre-historic caldera collapse -- displacing two-thirds of the island.
These events generated a series of giant waves, or tsunami, which steepened as they reached shallow waters. Lava forming islandsThese waves swept across the coastal lowlands of Java and Sumatra on either side of the Sunda Strait, killing an estimated 36,000 people and destroying many settlements. As an illustration of the forces involved, a government gunboat, the Berouw, was carried nearly 3 km inland and stranded behind a small hill 9 m above sea-level (the crew of 28 were amongst those who died). The violence ended abruptly, leaving a greatly re-shaped archipelago. In the centre of the caldera, where there had once been a substantial island, the sea-floor was reached at a depth of over 250 m. The three remaining islands were greatly re-shaped, and in places extensive new land surfaces had been created by the deposition of great thicknesses of pyroclastic ashes where once had been nothing but the sea. On the persisting areas of land, an average of 60-80 m of these ashes had been emplaced. The resulting landscapes were completely barren, and as far as can be established, no life survived. Plants and animals soon colonized, and the ecosystem re-building began -- a story we will come back to. Down in the depths of the earth, the emptied magma chamber will, once again, have begun to fill, eventually creating sufficient pressure to begin the construction phase of the cycle once again, naturally, pretty much in the center of the caldera
CHILD OF KRAKATAU
The Child Grows
plumesVolcanoes typically build up in fits and starts. After 1883,
Krakatau was dormant until 1927, when a new cone began to build at the
edge of the 1883 caldera. In 1928 alone, 22,358 earth tremors were
by a temporary volcanological observatory on the island of Panjang,
while eruption plumes were seen to reach 1,200 meters high. However, the
first three attempts to break the surface formed only temporary
ash-cone islands, which were destroyed by marine erosion and submarine
sliding on the steep slope of the submerged caldera. The second of these
islands was visited by a party of scientists in May 1929, shortly
before it slipped back into the sea. They collected several insects,
including a large black cricket and a brown ant. The present island, the
fourth, emerged in August 1930, and over the next few years, it
alternated between periods of quiet and rapid growth. At times,
particularly in the early 1930s, the eruptions produced huge quantities
of fine ash, which, aided by the alternating monsoon winds, have been
deposited on the developing forests of Panjang and Sertung islands, a
few kilometers distant (in opposite directions), causing extensive
damage. By September 1932, the island was 47 meters high and had a
typical low wide crater some 700 meters in diameter. By 1933, the height
had increased to 67 meters, and by 1941, it had doubled again to reach
1940s was a period of relatively little activity, but in 1952 and 1953,
the volcano sprang back into action, producing large quantities of
ejecta. This was produced in such quantities and to such heights (clouds
reaching 4,000 meters at times) that once again it was carried across
to Panjang and Sertung islands, damaging as much of 90 percent of their
forests to a degree visible from boats passing through the group. On
Anak Krakatau itself, the colonization of plants and animals was
abruptly halted by these eruptions, as the vegetation was more or less
eliminated. A new, high inner cone formed, that was about 500 meters in
diameter, enclosing a new crater lake. The records then indicate a
further period of inactivity, until 1958, with further ash eruptions
occurring over the period to 1963, during which some traces of ash
reached sites on the coast of Java, some 40 kilometers distant.
This young and active volcano has been growing
around 6 feet a year and still continues doing so. It grew by the accumulation
of ash, and suffered a devastating eruption in 1952, and other very destructive
one in 1971. It is now 300 m high and 5 Km in diameter, and is still active
spurting fire and cinder, this like moonlike landscape. It is lonely volcanic
island in the middle of the sea. The northeast coast, north foreland and east
foreland are now vegetated; the succession of vegetation is still at an early
stage, Casuarinas equisetifolia (cemara) being the dominant tree.strait area
were devastating, killing more than 36.000 people. That total volume of
material ejected by the eruption is estimated at some 18 - 21 cubic kilometers,
30 km high into the atmosphere with an ash cloud circling the earth several
times. Causing " blue suns" range moons" in Europe and
North America .
The amount of the sun's energy reaching the
earth was reduced, and in the year or two that followed, annual average
temperatures in the northern hemisphere were than usual. Generally rough except
Anak Krakatau as its volcanic activities sustain the overall height. In 1976 it
was only 169.67 M. in 1973 it was 189.48 and the last measurement was in 1985
when its height was 240 m, and was in 2008 more than 300 m.
rough except Anak Krakatau as its volcanic activities sustain the
overall height. In 1976 it was only 169.67 M. in 1973 it was 189.48 and
the last measurement was in 1985 when its height was 240 m, and was in
2008 more than 300 m.
primary vegetation includes the Kilangir (Chsiocheton Microcarpus),
Ketapang (Terminal Catppa),Melinjo (Gnetum Gnemon),Mara (Macaranggo
Fanarius),Cemara (Casuarina Equisetifolia),Waru (Hibiscus Filioeus)
Kampis (Hemadia Peltata), Hampelas (Ficus Ampelas), Cangkudu (Morinda
many animal to see, how ever if we are lucky enough, you might see the
Bottle Nosed Dolphin (Delphmus Delphie), Flying fox (Pteropus Vampirus),
Monitor Lizard (Varanus Salvator), Green Turtle (Cholonia Mydas),
Champeleon (Calotes Cristaleus), or Python (Python Sp), Birds include
the stork Billed “ Kingfisher (Tonyseptra Galatea), Common Tern (Stama
Hirundo) and white " Bellied sea Eagle (Heliastur Leucogaster).
Anak KrakatauThe Volcano Today: Will It Blow Again?
the mid-1990s the island had overtopped both Panjang and Sertung
islands, reaching a height of about 300 meters, with a diameter varying
between 3 and 4 kilometers. It has some way to go before it reaches the
height of the last fragment of the 1883 volcano Rakata, at some 780
meters. What are the chances of the cycle of growth and violent
destruction repeating itself? Volcanologists have a number of means of
assessing the likelihood of catastrophic eruptive activity. One
important measure is the silica content of the ejecta. As the magma
increases in silica content its viscosity increases, making it more
difficult for contained gases to escape. When they do, there is a
cataclysmic eruption, and silica content then falls to begin the cycle
again. The Krakatau data broadly fit this Magmamodel, and do not suggest
that another caldera collapse event is imminent. But you can never be
certain with volcanoes. In any event, it is not a volcano to take
lightly. Over the last 70 years, it has deposited something like a meter
of volcanic ashes on Panjang and Sertung islands, and has repeatedly
cut-back the development of its own ecosystems. When in full eruption,
it is an awesome sight, with huge volcanic bombs thrown hundreds of
meters from the eruption center, and great plumes of ash ascending many
hundreds and sometimes thousands of metres. Recent outpourings of lava
have also been spectacular, for instance, in November 1992, a four day
period of activity saw 35,650 square meters covered by lava of about 5
meters in thickness -- an estimated volume of over 2 million cubic
Eruptions from Krakatau (Anak Krakatau) :
1680-81, 1684, 1883 (Plinian eruption), 1927-30, 1931-32, 1932-34,
1935, 1936, 1937, 1938-40, 1941, 1942, 1943, 1944, 1945, 1946, 1946-47,
1949, 1950, 1952, 1953, 1955, 1958-59, 1959-63, 1965(?), 1969(?),
1972-73, 1975, 1978, 1979, 1980, 1981, 1988, 1992-93, 1994-95, 1996,
1997, 1999, 2000, 2001, 2007-8, April 2009-early 2010, Oct 2010 - March
The Journey to the island takes 1 : 30 hours on a good day in a normal fiber glass boat, and the best time of year to make the trip is between March and October. During the monsoon season (November to April) the time taken may be very much longer and the journey will be uncomfortable, although there may be storms in any month of the year. It is advisable to cover up well during the trip-even on overcast days one can badly sun burnt in a open boat at sea.
Keep your eyes open, and you m ay see a Frigate Bird soaring high overhead, flicking its scissor-like tail as it changes direction with hardly a flap of its wings. You will almost certainly spot flying fish making their long low glides above the sea's surface. Some of the them "fly" for tens of meters, and airborne for several badul islandsecond. Dolphin often come You may also be lucky enough to see a White-Bellied Sea Eagle as you approach the islands. It has a slow, gliding flight with the wings held in a shallow "v" as it soars, searching for sea-snakes, fish and crabs swimming near the surface. As you near the archipelago, the triangular silhouette of Rakata. The island takes its name from Krakatau's largest volcano, of which it is the remaining half. Cloud often covers the peak down to about 550 m, and above this height the forest begins to take on a different character. Mosses festoon the branches of trees, which are stunted at the peak. To the south (near the left side of the island as you approach) is a bay in which a settler named Handl lived with his family for a few years from about 1915. There have been no other permanent inhabitants on the island since 1883, although fishing boats visit the archipelago regulary, the waters within the island group often being calmer than the open sea.
Panjang, formally called Land island, and some times known as Rakata Kecil, was never part of Krakatau, but was once a part of Krakatau's huge predecessor "Acient Krakatau" Like Rakata and Sertung, it was covered in tens of meters of hot ash in August 1883, and this has been eroded over the past century into v-shaped gulleys separated by sharp ridges. Like the other two islands, it is now covered in forest. Some of the valleys are now "hanging" because the ash cliff has been cut back by the action of the sea so that the valley floor now opens at a considerable height above the shore. To your right, on the south western point at Panjang, the lava rock of "œancient Krakatau" can be seen near the base of a small cliff.
Now, to your left as you round its northern point, Rakata's huge vertical cliff towers above you. Again, towards its base, the layers of Ancient Krakatau's laval rocks may be seen, with ash layers between them, evidence of successive eruptions centuries ago, Casurainas (cemara) cling to the cliff, they cannot tolerate shade, and on most other parts of the island they have been overgrown and thus eliminated by other forest trees. Landslides are frequent on this cliff face is not the former vent of the volcano, but a landslide channel from close to the summit. Piles of rubble, the result of landslides, can be seen at the base of the cliff. At the far end of the cliff are the black rocks of Zwarte Hoek. where there is a small beach
As the boat moves under the cliff, remembered that you are traveling over the submerged caldera of Krakatau. The cliff continues almost vertically under the water below you to a depth of about 200 meters. To your right, if the sea is calm, you may be able to see Bootsmanrots behind you. These rocks, often with seabirds, usually terns, roosting on them are a favorite spot for shark fisherman, and shark's fins can occasionally be seen cutting the waters over the caldera. The rock are Krakatau's caldera rim which projects above the water at this point. Apart from Rakata itself, they are the only other piece of Krakatoa visible above water today. Of course, no one, could have been in this place before August 1883. Your boat is travelling along a line which at the time would have been covered by thousands of tons of the island Krakatau, which extended far to the north beyond the island Anak Krakatau to your right.
Moving past Zwarte Hoek and heading towards Sertung, you will notice, beyond the point to your left, a long sandy beach where the green turtle (Chelone Mydas) nests, and just out to sea two large isolated '"stacks" one of which has been perforated by the sea. These light-coloured cliff stacks, and the cliffs along Turtle Beach, are composed of ash deposited in the 1883 eruption , and give you an idea of the depth of ash that covered the island at that time. The stacks have been able to persist because they are on a basement of lava which has prevented the sea washing them away. Ahead is Sertung, the third member of the trio of islands that are remnants of the huge "Ancient Krakatau" volcano. Sertung was enlarged by Krakatau's 1883 eruption to more than twice its size, and is now virtually composed of ash from that eruption.
To your right is the presently active volcanic island, Anak Krakatau, "child of Krakatau". This is an apt name. for the island emerged from the sea in 1930 from Krakatau caldera, roughly in line with its three former volcanic craters and between the sites of the two northern ones. The lava field you see is composed of a number of different flows, the most recent one (1980) being the darkest. Lava did not appear until some time in the 1960s, and this was important in protection the rest of the island from erosion by the southwestern currents. Before the 1960s Anak Krakatau had emitted ash only, but at such a rate and frequently enough for it to grow, in spite of the marine erosion.
As you pass north along the east coast of Sertung, you will see the PHPA post in the trees near the shore, below what is probably the only permanents spring on the islands. A few hundred meters beyond the PHPA building the vegetation changes quite abruptly from mixed secondary tropical forest to a Casuarina (cemara) woodland. The cemara are growing overy young part of Sertung's, its narrow tongue or 'spit'. The spit has been formed by the sea wearing away the ash cliffs of Sertung's west coast, and the currents carrying the material to Sertung's northern point and depositing it there. The spit is "moving" the beach that you see is being added to, and if you have time to walk the 100 meters or so across the narrow neck of the spit you will see that the west cost is being cut back by the surf. So the cemara trees, which were also an early stage in the colonisation of Rakata by plants, are never subject-ed to shade by other forest trees because the "spitâ" on which they grow never becomes old enough for the other trees to establish themselves. In fact, at the present rate of movement, no particular point on the spit can ever become more than 10 to 20 years old before becoming part of the west cost, and being washed away.
As you leave Sertung and move back towards the northern foreland of Anak Krakatau, with Rakata's cliff looming up beyond in the middle distance, you are travelling over the northern end of the submerged remains of Krakatau itself. Anak Krakatau is large barren, being made up of ash fields or lava, but on the northern foreland you can see a number of cemara trees and an extensive grass land os "alang - alang" and wild sugarcane. This grassland was a very early stage (before the cemara) in the plant colonization of the other islands, and the process is being repeated here on Anak Krakatau. Moving around to Anak Krakata's landing beach on the eastern foreland, you see more cemara woodland-this foreland is at a later stage of plant succession than the northern one.
Going ashore, you will notice other trees and saplings here and there among the cemara and wild sugarcane the forest is beginning to change to mixed secondary forest. Two species of fig trees are present, and they were first seen fruiting in 1985. There are three species of bats on the island (of a total of 11 on the archipelago), two kinds of Dog-faced fruit Bat and a Rousette . All there are fig eaters. Also two species of fruit-eating pigeons (Pink-necked Pigeon and Cuckoo Dove) as well as the Yellow-vented Bulbul and the striking, yellow and black, black-napped Oriole now live on the island. These birds and bats spreads figs by drooping or excreting their seeds, and probably were responsible for bringing the fig species to the Krakataus from the mainland, and to Anak Krakatau from other islands. They will probably bring more fig species to Anak Krakatau, and the change towards mixed forest is likely to accelerate in the next few years.
You may see the bright yellow breast of the tiny Olive-backed Sunbird as it seeks nectar and insects, clicking as it goes, and perhaps, its nest hanging from a cemara branch. Keep a lookout also for another very small, yellow-breasted bird, the Flyeater, flying from branch to branch in the cemara, or a small flock of a large bird, the white-breasted Wood-swallow, perhaps six or seven of them perching together along a high cemara branch. Almost Kingfisher, greenly-blue with a white "collar". This is one of the most successful colonists on this islands. It makes nest holes in the large spherical termite nests that you see here and there in the cemara trees, and noisily and aggressively defends its nest-site from other intruding birds, such as the wood-swallows.
Only about 14 hectares of Anak Krakatau are vegetated, and you will get an idea what a small part of the island this is if you climb to the marker on the rim of the outer ash-cone, a strenuous walk, to be attempted at mid-day only by the fit. Yet this small area of woodland support about 22 of the 36 species of land birds (not counting migrants) now know on the islands! So of the 36 land bird species that have colonized the islands from Java and Sumatra in the hundred years or so since 1883, 22 of them have managed to establish themselves on Anak Krakatau's eastern foreland in the past 30 years or so (Anak Krakatau's 952 eruption destroyed all its vegetation) There of the 9 species of reptiles on the islands have also become established on Anak Krakatau. The large, very common monitor (Varanus salvator) a relatively of the famous Komodo dragon, is a good swimmer and feeds on crabs and turtle eggs. The common Ceckhack Gecko , and the "flying" (really gliding) paradise Tress Snake, have also colonized Anak Krakatau, the last two probably by means of floating vegetation or logs, which you will have already noticed are common on the beaches. Only one of the 19 species of land snail on the islands has yet reached Anak Krakatau â€“ it was first noticed on Rakata in 1933. There are rats on the archipelago " the Houses rat on Rakata , and the Country rat on Panjang and Sertung. Only one individual (a House rat) has ever been found on Anak Krakatau in 1985.
The Tokay (Gecko gecko), which is a gecko-eater, and the black eagle, python, and False vampire bat (which are also predator) are present on the other islands but have not yet been found on Anak Krakatau, probably they have not colonized it because they do not yet maybe a sufficiently reliably food supply there. Also, several forest birds, such as the Brown-capped Woodpecker and Orange bellied Flowerpecker, which require large trees, have not yet colonized this island although they are present on the others
For the study of change, both physical and ecological change, the Krakataus are a natural laboratory-in fact two laboratories in one. Change both in the archipelago since 1883, and on Anak Krakatau since 1930, are being studied. So that this work is not made more difficult by artificial changes brought about by humans, please keep to the trails, do not wander about the archipelago with out a guide, and make sure that you neither bring to, nor take from the islands any living things (seeds, fruits, insects, etc). Please take yours refuse back with you, so that other visitors may enjoy the natural beauty and ponder on the fascinating history of this unique group of islands