Wednesday, 26 October 2011

Little monkeys

These charming creatures are "saguis" (marmosets), in fact "Saguis de cara branca", White headed marmosets (Callithrix geoffroyi). One of the tamest wild animals, they are great favourites of tourists, eagerly taking fruit in their little hands. Without tourists, they have to fend for themselves, groups travelling up to 2 km through the forest. They eat fruit and any small creatures they can find, insects, snails or even frogs. They also eat a surprising amount of gum from trees and lianas, either gouging wounds in trees or searching for wounds made by insects. Gum apparently has a lot of carbohydrates, so it is sweet and gives lots of energy to little monkeys.

And saguis are little, which means they need lots of high energy food, but they can turn out to be food themselves. Hence the frequent nervous glances up to detect any eagles or falcons. Mothers carrying young seem to settle for fruit and gum, hunting for tasty insects takes too much attention, and they are too ungainly to bolt if needed. If predators appear there are basically two options. If they see a raptor, there is a brief cry and then they freeze still under cover. But if it is not immediately dangerous, a cat on the ground for instance, they will mob it - harassing it from above as a group and making loud "tsik" calls. Strangely, it has been shown that being part of a "mob" actually reduces rather than increases monkey stress - it is tempting to extrapolate that to humans!

One curiosity of saguis, and other new world monkeys, is that some individuals are trichomatic, and some dichromatic. What does this mean? Humans and higher apes have three different colour cells in their eyes, in combination they can distinguish up to 1 million colours. Most mammals have just two types, so can distinguish only about 10,000, kind of equivalent to colour blindness. So why are some monkeys one type, others another? Apparently trichromatic monkeys are better at finding fruit, especially when its red, but dichromatic monkeys see better in the low light of dawn and dusk, so it all balances out in the end.

Saturday, 22 October 2011

The Owl of Buenos Aires

No, this is the "other" Buenos Aires, a pretty valley in the hills above the Brazilian coastal town of Guarpari.

On a visit there I saw various birds flitting around, from finches to a circling eagle, but the one that really caught my attention was this Burrowing Owl (Athene cunicularia - say "cunicularia" and you will see how it is a good name for an owl!).

I have blogged about Burrowing owls before ( , so for now, here are just some pictures.........

... and his (her?) burrow

Friday, 14 October 2011

..... Not really

There are some creatures that live on the edge of reality, from Bigfoot to the Loch Ness monster. Brazil has it's share too.

The Mono Grande, Didi or Maricoxi

The Wild Man of the Woods. There have been reports of "ape men" in the Amazon region since the days of the conquistadors, Pedro de Cieza de Leon reporting Indian legends of them in 1533, and Francis Drake recorded similar rumours. "Sightings" have surfaced every now and again since. There was even a photo published in the Illustrated London News in 1929, and a scientific name suggested (Ameranthropoides loysi).

Reports have been remarkably consistent from 1769 onwards. The Mono Grande are apes about 5 ft tall, more or less upright and covered in short dark hair. If angry they throw sticks, or their own faeces in one report (which might be more effective). It has to be said that these reports have not been universally accepted, or at all in a serious sense. The fact that these forests are home to both Indians who are about 5ft tall, and spider monkeys who are 3ft tall but covered in short black hair, has not gone unremarked.
As an aside, one of the most popular comedians in Brazil goes by the name "Didi".

The Mapinguari, Mapinguary or Isnashi

Once upon a time Brazil was home to giant ground sloths. It really was, their fossils have been found. They were very successful and spread throughout the Americas, some weighing up to 5 tons and with a reach of up to 17ft if standing on their hind legs.

Recreation of a Giant Sloth (conveniently with red hair) at Iowa Natural History Museum

It is suggested that some of these are the mapinguari (or mapinguary or Isnashi ) a large, noisy, smelly and red haired animal supposedly found in the rainforests of Brazil & Bolivia, the "fetid beast". The mapinguani has powerful arms and long claws, and can stand on its rear legs when threatened, which is very giant sloth like. After all, radio carbon dating shows they were still around in at least 2,700 BC (on Cuba), not so long ago, or maybe the mapinguari could be a folk memory passed down from that time. One intriguing connection is that the mapinguari is supposedly bullet (or at least arrow) proof and giant sloths had hides toughened against predators with small bony plates.

Giant Anacondas

Ok, these actually exist. The term "anaconda" refers to a group of similar snakes, but is usually used for the Common Ananconda (Eunectes murinus) which can be up to 22ft long, which is pretty impressive,
It's really hard to actually get a good measurement for various reasons. Firstly, anacondas are aquatic and so are difficult to see, or recover if killed. And to be measured they pretty much have to be killed, as 22ft of muscle is really hard to capture and hold in a straight line. Secondly, specimens don't preserve well, and skins can stretch up to 50% in the drying process.
But the ones we are talking about are bigger - much bigger. The renowned Britsh explorer, Percy Fawcett, reported in 1907 killing one measuring 62 ft long, and he had been told by a Brazilian Boundary Commission official of one in the River Paraguai of over 80ft. Through the 1920s, 30s and 40s there were various claims to have seen snakes of 60-70ft long though no hard evidence.

Percy Fawcett and the Giant Anaconda

Two little asides. Several witnesses report that, in addition to it's great length, the snake had glowing eyes, visible when the snake was underwater. Fawcett also comments on the awful stench, which local Indians claimed had a stupefying effect.

The Minhocao

Basically "Big Earthworm" in Portuguese, and that's what it looks like, a gigantic earthworm about 1 metre thick and up to 25 m long, with small horns. It is capable of taking cattle and of ruining orchards with its burrows. During the late 19th century there were reports from as far apart as Parana, Goias and Uruguay, mostly in waterlogged ground by rivers, but little since.
Now, there are creatures called caecilians, basically carnivorous legless amphibians which burrow in damp ground, and they can be up 5ft long. A large one of these and a very active imagination could maybe produce the Minhocao.

Legendary beasts of the Guarani

The Guarani are a tribe from the interior of Brazil, to the south and west. Their pantheon of gods includes some interesting examples of, er, speculative biology, such as ...

The Mboi Tui

The "snake-parrot" is just that, a huge snake with the feathered head of a parrot. He lives in marshes like the Pantanal and lets out a terribly loud squawk if disturbed. Actually, the Mboi Tui is just one of lots of "feathered serpents" found in American legends, Aztec and Mayan temples are full of them. If you want to look at it one way, this is suggestive of a shared folk memory - or cultural drift, take your pick.

The Ao Ao

The Killer Sheep. A huge animal resembling a sheep or peccary. Unfortunately it also has a large pair of fangs and is completely carnivorous. The Ao Ao eats only man, chasing its prey with a howling "Ao Ao Ao". It is implacable, chasing its chosen prey relentlessly until caught - climb a tree and it will dig to undermine the roots until you fall. Should you be faced with an Ao Ao the only way to escape is apparently to climb a Palm tree, as it dislikes these and will go looking for other prey.

More details on the cryptozoology can be found at.... The CryptoWeb web site

Sunday, 2 October 2011

Pigeons Everywhere

If you visit Rio for the World Cup or the Olympics you will see many beautiful and exotic sites, but one very prosaic one - pigeons. Even on Copacabana you will not see the ubiquitous seagulls of Northern Europe, but pigeons picking at the remains of ice creams and sandwiches left by tourists. They seem to quite like resting on the sand.

A pigeon on Copacabana beach

Brazil has various "pigeons", for instance the little Ruddy Ground Dove, but here we are talking about the Rock Dove (Columba livia), one of the most successful species in the world. They probably evolved in South Asia, but spread rapidly, fossil evidence showing that they have been in Israel, for example, for over 3,000 years. The first recording in the Americas was in 1606, in Nova Scotia, and they were later introduced through the Americas as domesticated birds. They are now virtually ubiquitous in towns and cities in Brazil - a recent study in the southern city of Porto Alegre found them to be the 2nd commonest bird, after house sparrows.

Why so successful?

a) Tolerance
Man isn´t always tolerant of pigeons, especially when they are eating his crops, but pigeons are extremely tolerant of man. How many other birds would by happy in the noise and confusion of Trafalgar Square? This allowed their domestication early in human civilisation, but also opened up a world of opportunity for wild pigeons. It didn´t hurt that cities are, to a pigeon, very similar to the cliffs their ancestors evolved in, so there are plenty of nest sites.

Pigeons on a castle wall in Tonbridge, England

b) Adaptability
Pigeons are the dogs of the bird world, in the sense that they have a huge potential for variation. Darwin noted this, devoting a whole section in the first chapter of The Origin of Species to differences in domestic pigeons - "the variation of the breeds is something astonishing" although "I am fully convinced that the common opinion of naturalists is correct, namely, that all have descended from the Rock Pigeon (Columba livia). "

So pigeons are adaptable, especially in....
c) Food
Pigeons are basically seed eaters, but as everyone knows, they will eat more or less anything. This is one of the reasons for their success, and results from a very forgiving digestive system which can cope with high carbohydrate or high protein food.

d) Temperature
How on earth can the same species be happy on a scorching Copacabana beach at 40 C and a bitterly cold English city at 0 C?

Pigeons in Reading, England in February. Happy?

The wonderful adaptability of pigeons spreads to thermoregulation, so that they can adapt themselves to temperatures even up to 60 C.
"Normal" birds will pant to lose heat, but adapted ones evaporate water from their skin. It´s not sweating as such, but they actually change the structure of their skin so that it has a much greater blood supply and is more hydrated. On the other hand, in the cold pigeons form an extra layer on their skin to stop evaporation, as well as eating even more than normal. Actually, pigeons prefer it warm as they can spend less time brooding baby pigeons and more time feeding (and so make more baby pigeons).

Flying rats?

It has to be said that communal nesting and a lack of delicacy over food does come at a price. Concerns have been raised over the hygiene, of pigeons, given that guano tends to be a prominent feature of their local environment. For example, 10 out of 33 pigeon droppings studied in in the city of Vitoria had Cryptococcus neoformans, a cause of fungal meningitis. On the other, these were old, dry, droppings, and the birds themselves when examined, er, intimately, they did not have the fungus, nor did other ones in Fortaleza. In other words, the guano had not been cleaned away and was just somewhere for the fungus to grow. So it could be argued (perhaps not very convincingly) that this is a lack of human rather than pigeon hygiene.

Pigeons probably do itch quite a lot. A study of 14 nests in the city of Manaus in the Amazon collected over 10,000 arthropods over 12 days, mostly mites. This was actually less than would be found in other parts of the world, probably because the local parasites have not quite adapted to pigeons yet.

How to have less pigeons

A pigeon having a drink on Copacabana

Various raptors will take pigeons. They form a large part of the diet of the Black chested buzzard (Buteo melanoleucus) and are taken by the Stygian owl (Asio stygius) and other hunters, but this is not exactly a control strategy. Spikes or wires to prevent perching work well locally, but just shifts the problems. The fashionable solution at the moment is bait treated with a contraceptive, and this is now being used around the world. A study in Ljubljana, Slovenia, found a 24% reduction in numbers over 3 years. Interestingly, the pigeons that remained were healthier, with fewer parasites.

But the problems of urban life not withstanding, pigeons have been valued by the Egyptians, the Romans, and rulers of ancient India and Iran through history, and they are one of the most successful species on the planet. Perhaps we should pay them a little more respect.