Hunter in the Night Sky

Look to the south and you will see the Southern Cross and Alpha Centauri, but look away from there from November to February and the most conspicuous constellation you will see is Orion, possibly the best known constellation on the planet! Conspicuous and visible from all over the Earth, everyone, from the ancient Egyptians to the Aztecs to the Aboriginal Australians has Orion in their mythology

As everyone knows, Orion is basically four stars, the arms and legs of the Hunter, surrounding his "belt".

A screenshot from Stellarium, 8pm 15th April

The bright red star is Betelgeuse, the strange name coming from the Arabic al-jauza (the name of the constellation) and abet, meaning centre or armpit, so Betelgeuse means "Orion's armpit". Be that as it may, Betelgeuse is huge, if it were placed in the centre of our solar system its surface would extend out to Jupiter. Huge, but not long for this universe being a decaying super giant - when it finally explodes it should be visible from Earth during daylight.

Opposite Betelgeuse is the blue star Rigel, the brightest star in the constellation. Again named from the Arabic, Rigel is a shortened form of Riǧl Ǧawza al-Yusra, which means basically "Orion's left foot". Actually Rigel is two stars, a binary system, which is why it's so bright.

The Belt, three stars together in a straight line, has many names. In Latin America it's known as the Three Marys, a reference to the three biblical Marys who came to the sepulchre of Jesus in the Gospels and were companions of a 4th Mary, the mother of Jesus. Mary Magdalene, Mary of Cleopas and Mary, mother of James. Of course the three stars of the belt are nowhere near each other, they just look that way from here. The star in the middle, Alnilam, is actually 375,000 brighter than the sun, but perhaps fortunately, is 1340 light years away.

The other two stars are Saiph and Bellatrix. Saiph again has an Arabic name, a corruption of saif al jabbar or "Sword of the Giant". It looks faint to us but that's because us humans cannot see UV light, in fact it's as bright as Rigel, but much hotter and most of it's light is ultra violet.

And lastly Bellatrix, the "Amazon star". Bellatrix is "Female Warrior" in Latin, and technically the star is an "eruptive variable" - thus this is perhaps a fitting name for the extremely dangerous, though barking mad, adversary of Harry Potter.

A New Rat

The world always needs more rats (doesn´t it?) and so you will pleased to know that a new one has been discovered! Drymoreomys albimaculatus is orange, hairy and lives in trees.

Actually, Drymoreomys albimaculatus are very, very, rare, even one of the authors of the paper describing them had never seen a live one. They live on the eastern slopes of the Serra do Mar, in the coastal Brazilian Atlantic rainforest from São Paulo down to Santa Catarina, at altitudes of 650 to 1200m. Which means cold damp forest with winter temperatures down to below 0 C, which is probably why they have unusually long thick fur. Although all the ones that have been caught were on the ground, they probably climb trees as they have long prehensile tails and special pads on the palms of their paws for climbing.


Drymoreomys means forest mountain rat, and albimaculatus refers to the white spots they have in their orange pelt. And that's about it. Their life cycle, predators, place in the ecosystem is a mystery. Goodness knows what they eat, probably everything, rats aren´t usually fussy.

The Sky at Night

The night sky of the Mata Atlantica can be as impressive as it's wildlife, and as difficult to see. Of course it depends where you are. By the coast, the tropical heat and humidity tends to cause clouds at night, even after after a day of burning blue sky, whereas in the mountains the clean air and lack of ambient light can open up a vista of millions of stars, or valleys silvered by a brilliant moon.


But to a northern European, the sky is strangely unfamiliar. Orion is still there, but the other stars are rearranged in new patterns. How to identify them? One way is the excellent Stellarium program I have been playing with recently, a free download from www.stellarium.org. The beauty of it is that it's completely customisable. Open the menu by passing your cursor to the left hand side and under [location] input your coordinates and a 360 view of your night sky at that moment will appear (you can find your coordinates in various ways, but the easiest is probably to just put your town/village's name in wikipedia). Find the star you are interested in and click on it to give a name and some basic info. You can also set it up to show the planets automatically, arrange the stars in constellations, increase or decrease the level of background light pollution, and many more things.

So what did I see? The first thing I tried was to ID a constellation I've seen many times from my south facing balcony, but never found in any books. That was because it is in fact 2 constellations, one of which is the most famous of the southern hemisphere.

The Southern Cross is part of the culture of Brazil, on the flag and even the name of a major football team, Cruzeiro. Trace a line from Gacrux, the red one, across to Acrux and extend it about 4.5 times and you are looking, more or less, due South.

Of course the constellations are an optical illusion, Beta crux is 350 million light years away whilst Gacrux is "only" 88. The red colour of Gacrux comes from it being a red giant, a huge, but dying, star, the colour giving it the local name of Rubidia, or "ruby like". In contrast Delta crucis is known as "Palida" or the "pale one". The two pointers, Alpha and Beta Centauri, are technically part of the constellation Centaurus, but on a hazy night, or with lots of ambient light, they seem much more part of a tail to the "Y" of the Cross. Alpha Centauri is very bright, and for two reasons, it's actually three stars, two of which orbit around each other, and one is the closest star to Earth, at 4.2 light years away. Because it is so close Alpha Centauri is found in all sorts of science fiction, from Lost in Space, via Babylon 5 to Avatar, but of course these stars are also found in local mythology, showing local priorities. For the Xingu indians, the Southern Cross is the Curossow bird, whilst Alpha and Beta Centauri are a bird trap.

A life on the ocean waves

Fly to Brazil from Europe or Africa and you will pass over thousands of miles of ocean. As you look down on the endless waves you might reflect on life below - perhaps you imagine you see a whale spouting, or a fishing boat trawling for cod. If you've already experienced Brazil and it's teeming millions of insects, you might wonder if there are any of those down there too. In fact, in all the world there are only 5 species of ocean going insects, all from the same genus, Halobates, and only one of these H. micans, is found in the South Atlantic.

Dias & Lopes 2009. Occurrence, distribution and abundance of Halobates micans Eschscholtz, 1822 (Heteroptera, Gerridae) along the southeastern Brazilian coast. Braz. J. Biol. vol 69.

Halobates micans, the Sea Skater, is in the same family as the pond skaters, and you can see why, with it's long legs and antennae. They live in a purely 2 dimensional world, they can't fly and die if immersed under water for long, though they cover themselves with water repellent and are covered with tiny hairs which trap air, so they are very buoyant. Instead of flying or diving they skate across the sea surface at up to 1m per second, hunting for prey. Well, very small prey, as their bodies are only about 5mm long, so plankton, or perhaps fish larvae trapped on the water surface. The weak link is egg laying, for which they need a solid object. This can be hard to find in the open ocean and they will use anything, really anything, seaweed, dead jelly fish, lumps of petroleum. A plastic gallon jug was found to have 70,000 eggs attached!

Zoologische Staatssammlung München Halobates micans; Eschscholtz, 1822; Meerwasserläufer, Wikicommons

Sea skaters seems to be fairly common, though not near the coast, or too far south where the water is cold. But why does he have the whole south Atlantic to himself? After all there are plenty of insects living in fresh water. Well, salinity is a problem, although the salt marsh mosquito, for example, can tolerate 3x this level. Worse maybe is the problem of breathing. Insects need access to air, at least occasionally, and the rough and tumble of the ocean may drive their little bodies too deep into the ocean for them to return. This is maybe why the only insects there are restricted by super-buoyancy to the surface.


The ocean can, from above, appear like a desert, but for Halobates it's actually worse. Most desert animals can burrow into the sand to escape the heat of midday, or predators, but Sea Skaters are stuck on the surface with nowhere to hide. The sun burns down, with levels of UV that would fry most creatures, but Halobates is shielded by a layer of very dark UV protection in it's upper cuticle, which blocks pretty much all UV light. Then there are fish and sea birds attacking from below and above, which Sea Skaters avoid by jumping several centimetres into the air, away from the water surface.

Put all this together and you start to see why, of over 1,000,000 insect species, there is only one in the vastness of the South Atlantic, the little known Sea Skater, Halobates micans.

If you can lay your hands on Antenna, the journal of the Royal Entomological Society, there is an excellent article on Halobates there. Alternatively, there is a good web resource at http://www.zmuc.dk/EntoWeb/Halobates/HALOBAT1.HTM

Dinosaurs on the beach

The Ilha de Cajual, in the north of Brazil, is today a tranquil, restful, place. 95 million years ago it was a little more, shall we say, lively, with pterosaurs, giant turtles, and a 14 meter long, 7 tonne crocodile running towards you on it's hind legs!

Just recently researchers at the Universidade Federal do Rio de Janeiro have been displaying fossils of Oxalaia quilombensis, the largest animal of it's type ever found in Brazil. Actually, it wasn't really a crocodile, but a spinosaurid, a type of reptile with a huge crocodile like head that could walk on it's hind legs with a distinctive "sail" on it's back.


So what was life like for Sr. Oxalaia? Well, like most spinosaurids he probably spent most of his time in water - believe it or you can tell this by oxygen isotope analysis of their bones. His skull is characteristic of a predator of fish and small animals, not large prey, and in fact most Spinosaurids tend to be found with fish fossils The need for lots of small meals suggests he was probably quite an active hunter. The sail is a bit of a mystery though, some people say it helped spinosaurids control their temperature, some say it was for display, like a peacocks tail. Could be both of course.

A typical spinosaurid skull

Why "Oxalaia quilombensis"? Well, quilombensis refers to the quilombo, a group of runaway African slaves who were once established on the Isha de Cajual. And Oxalaia is named after Oxalá , one of the highest gods of the Yoruba religion, which started in Africa and spread to the Americas. This African motif is actually very appropriate as the spinosaurids originated there - north Africa and Brazil have so many reptile and fresh water fish fossils in common from this period that there must once have been a land bridge between the two. Oxalaia had plenty of cousins in Africa.

If you would like to know more, Oxalaia quilombensis is properly described in...

Kellner, Alexander W.A.; Sergio A.K. Azevedeo, Elaine B. Machado, Luciana B. Carvalho and Deise D.R. Henriques (2011). "A new dinosaur (Theropoda, Spinosauridae) from the Cretaceous (Cenomanian) Alcântara Formation, Cajual Island, Brazil". Anais da Academia Brasileira de Ciências 83 (1): 99-108.

Darwin's Carnival

It's Carnival time in Brazil. Thousands of people have been working all year on wonderful costumes and floats for this moment, and so it is especially gratifying for this blog that one of the winners, Uniao de Ilha, chose as their theme the English biologist Charles Darwin.

Darwin and his manuscripts

Although most people know of Darwin's voyage to the Galapgos on HMS Beagle, not many know that he stopped off on the way in Brazil. Fortunately, a friend has been kind enough to give me a copy of his diaries.
"It was impossible to wish for anything more delightful than thus to spend some weeks in so magnificent a country. In England any person fond of natural history enjoys in his walks a great advantage, by always having something to attract his attention; but in these fertile climates, teeming with life, the attractions are so numerous, that he is scarcely able to walk at all." he wrote in his journal.


After a quick stop at the volcanic island of Fernando de Noronha the Beagle next made landfall at Salvador in Bahia, where Darwin took the opportunity to explore inland.
"The day has passed delightfully. Delight itself, however, is a weak term to express the feelings of a naturalist who, for the first time, has wandered by himself in a Brazilian forest. The elegance of the grasses, the novelty of the parasitical plants, the beauty of the flowers, the glossy green of the foliage, but above all the general luxuriance of the vegetation, filled me with admiration. A most paradoxical mixture of sound and silence pervades the shady parts of the wood. The noise from the insects is so loud, that it may be heard even in a vessel anchored several hundred yards from the shore; yet within the recesses of the forest a universal silence appears to reign."


Next stop was Rio. Here an Englishman, Patrick Lennon, offered to take Darwin on a trek inland...
"Leaving the coast for a time, we again entered the forest. The trees were very lofty, and remarkable, compared with those of Europe, from the whiteness of their trunks. I see by my note-book, "wonderful and beautiful, flowering parasites," invariably struck me as the most novel object in these grand scenes. Travelling onwards we passed through tracts of pasturage, much injured by the enormous conical ants' nests, which were nearly twelve feet high."

The tree of life

There is material for a 100 blogs in Darwin's journals, which can be found online at
www.literature.org/authors/darwin-charles/the-voyage-of-the-beagle/

For now I will only add a passage from the journey after Rio, down to Montevideo
"In our passage to the Plata, we saw nothing particular, excepting on one day a great shoal of porpoises, many hundreds in number. The whole sea was in places furrowed by them; and a most extraordinary spectacle was presented, as hundreds, proceeding together by jumps, in which their whole bodies were exposed, thus cut the water. When the ship was running nine knots an hour, these animals could cross and recross the bows with the greatest of ease, and then dash away right ahead. As soon as we entered the estuary of the Plata, the weather was very unsettled. One dark night we were surrounded by numerous seals and penguins, which made such strange noises, that the officer on watch reported he could hear the cattle bellowing on shore. On a second night we witnessed a splendid scene of natural fireworks; the mast-head and yard-arm-ends shone with St. Elmo's light; and the form of the vane could almost be traced, as if it had been rubbed with phosphorus. The sea was so highly luminous, that the tracks of the penguins were marked by a fiery wake, and the darkness of the sky was momentarily illuminated by the most vivid lightning."

Jaca

The Jaca (Artocarpus heterophyllus) is one of several fruits well known in Brazil, but unlikely to find itself in a supermarket in England. Actually it's originally from Asia, and is for example, the national fruit of Bangladesh.

The Jaca, or Jack fruit to give it it's English name, holds the distinction of being the largest fruit in the world, reaching an incredible 36 kg in weight! Because of this the fruit are not out on the branches, which would break under the stress, but hang directly from the trunk. The trees themselves are large and stately reaching up to 25m high.

As I said, the Jaca originates in Asia, and was probalby transported to Brazil from Kerala by the Portuguese. But it flourishes in the Mata atlantica, and indeed is sometimes considered a pest! It's fruit are eagerly devoured by coati, which then deposit the seeds around the forest, where the fast growing Jaca (1.5m/yr!) often out strips native species. This also artificially boosts numbers of coati who then go on to raid nests for eggs and nestlings. Because of this national parks often clear wild Jaca saplings, with, for example, over 50,000 being culled from the Tijuca Forest park near Rio between 2002 and 2007.

Eating a jackfruit is, problematic. Firstly, mature fruit emit a strong, distinctive smell, said to resemble rotting onions. Secondly, the fruit is covered in spines, thirdly cutting the fruit relesaes a sticky latex which will accumilate on knives and skin unless pre-coated with cooking oil. And fourth, the flesh tastes of banana, which is itself enough to dissuade this author!

Although there seem to be many delicious recipes for Jaca from Asia, I could not find any from Brazil. The fruit is ususually eaten fresh, or as a juice. Take care though, the flesh is hard to digest, and, anecdotally, several people have died from getting carried away and eating a whole one!