Our last meeting took us on the path of insects, spiders, turtles, frogs, toads and snakes; animals that are loved by some and hated by others…today we will go back in the wilderness of French Guiana but looking for different animals, birds and mammals.
Birds and insects are certainly animals one simply cannot avoid even for a very short sojourn in French Guiana. There are some 9,800 different bird species worldwide and 700 have been documented in French Guiana, a rather impressive percentage. Out of this large number 58 species are migratory or passing by and do not breed within the boundaries (they are to be mostly found in coastal areas, swamps, muddy places). About 500 species are totally pledged to forest and some are typical images of South America like the various toucans, parrots, hummingbirds and the stunning Rupicola rupicola or "cock-of-the-rock."
Fruit-eating birds may move within the territory by following seasonal fruit producing which vary according to rains but they basically stay in a limited area. Though birds are only a small part of the whole forest animal population, they do have a very important part to play both in seed dispersal and insect population control. A recent study has shown that out of a large panel of birds of French Guiana, 51% are insectivorous, 17% frugivorous, 15% omnivorous, 8% carnivorous, 5% nectar-eaters and 4% of fish-eaters which can give an idea of the impact on insects. Another study has revealed that 80% of the seeds are disseminated through zoochory (dispersal by animals) which of course takes in consideration all fruit-eating species from bats to monkeys but birds again do play a large role here.
Birds can be found in all the different biotopes available: savannahs, forests, rivers, coasts, swamps etc. Some stay close to the ground and feed on small insects, slugs, fruits and seeds. Those will take ample advantage of a colony of legionary ants roaming the understory, as all living creatures will hastily flee the army of tiny soldiers, small insectivorous birds will happily fly here and there catching preys that try to get away. My strolling in the forest was greatly enhanced by the amazing capacity of my host Johann to identify an amazing number of birds just by the song they produce, then we could slowly get closer and enjoy the view of the singer using telephoto and binoculars, later on climbing up the highest trees to reach species which stay in the canopy.
Rupicola rupicola(Photo J.Tascon)
So I can tell you that the concert is permanent, either alarm calls from the ‘gendarme' (policeman) Lipogus vociferans, which will shout as soon as he spots large mammals, specifically those with shoes and hats, mating calls, social calls, an unceasing chatter. I could not remember the names of the numerous birds I saw but I recall an abundance of bright colors and rapid movements through branches and leaves! Several species of raptors can also be seen; most often perched on dead trees which bare branches allow them to efficiently spot any available prey in the area.
Let the birds sing and fly and now we can turn to mammals; there are 191 different species in French Guiana (according to the latest study of February 2011) out of which half is made of bats, I did not stay long enough to meet all of them and some are quite rare or even endangered because of over-hunting, so let us see just a few of them. I will start with a rather strange one, Trichechus manatus, the West Indian Manatee, an aquatic mammal which can reach 3 to 6m (9 to 18 feet) long and weight 200 to 600 kilo, it lives in the Ocean and feeds on different plants, hence absorbing also small fishes, snails and crustaceans stuck on the leaves. It is related to the dugong of Indian and Pacific Oceans.
Bradypus tridactylus (good guy!) J.Tascon
Now for another curiosity; this time I had the chance to see it and actually it was quite an encounter. I was driving towards the forest with my friend Johann in order to go climb some giant trees when a friend of him called on the mobile and said we had to go urgently for a rescue on the new road to Brazil. So here we go, hit the proper road and soon stop in front of a crash barrier where was hanging upside down a sloth. Now, there is something one must be aware of, there are actually two sloths in French Guiana (out of the six known species) , the good guy and the bad guy or Bradypus tridactylus versus Choloepus hoffmanni ,the three-toed sloth and the two-toed sloth. It sounds rather funny but one should know which one he has to deal with. The three-toed sloth is about the size of a dog, with short ears and tail, long hair with a grey greenish color and bears long curved claws, it lives in trees where it feeds on leaves and comes down to the ground about once a week to defecate or cross a river as he his a good swimmer. This animal is famous for being very slow and quite and you can hug it and play with it. The two-toed guy is roughly similar in aspect and habits but if you come too close you may loose parts of your body...it has two very sharp claws and can become amazingly fast and vicious with them, so you better watch out! Johann of course had warned me about this and when we came close enough he said ‘ho-ho, this is a two-toed client here!'
Choloepus hoffmanii (poor bad guy!)
This one had apparently tried to walk across the road but had been frightened by a car and reacted by hanging on
Johann to the rescue!
the first thing available, a crash barrier where it could not hide efficiently and would be victim of the first passerby carrying a weapon as they are hunted for food. So Johann took out his special snake-catching-device, a kind of wooden stick ending with a running knot and caught the animal's neck while I had to unsnap the rear claws strongly clenching the barrier. After some struggling, grunting and sweating we eventually managed to free the poor guy and let it go back in the wild where he soon disappeared. Johann's stick had deep scars made by the teeth and claws, the same treatment applied on our arms or hands would definitely have ended in a painful mess! The strange greenish color of those animals comes from two different cyanobacterias living amongst their hair, which also harbors many different insects, a whole ecosystem!
Other mammals which I happened to be around more often than in my usual life are bats. They are called chiropters (from the Greek ‘chiro' for ‘hand' and ‘ptere' for ‘winged') by scientists and are the only mammals able to fly. There are some 102 recorded species in French Guiana out of an estimated total of 110, to be compared with the 32 species for the whole Europe.
While European bats are all exclusively insectivorous the South American species have strongly diversified their food sources; some do feed on insects of course but others will feast on fruits, nectar, pollen, fishes, meat (birds, rodents, other bats) and even blood. The haematophagous ones number only three species of vampires, two are present in French Guiana, Desmodus youngi which will only feed on bird's blood while Desmodus rotundus is not that fussy and will drink from any source available; birds, mammals, amphibians. They can be a problem for cattle and will land on men if available (another reason why you do not want to sleep in your hammock without a mosquito net). Though they are able to ingest as much as 40% of their own weight they would not suck you dry but can inoculate rabies. So now the reason why I had a close look at those nocturnal animals is that I was hosted in Cayenne (French Guiana main town) by Vincent, a friend who works as naturalist and was just leaving with a small group of scientists for a few days of field work on bats when I dropped by. They just left me time to pack a couple things and we took off to Yalimapo, an Indian village on the Guiana-Surinam border.
Once arrived we strung the hammocks with mosquitoes nets attached (you know why!), got the paraphernalia out of the cars and proceeded to setting nets. Those are made of very fine synthetic threads and once deployed will be five to ten meters large and three to six meters high, the same ones used by ornithologists to catch birds. With sunset the first bats start flying out of their hideouts and are to be freed rapidly from the nets which they would otherwise soon destroy. As I was not vaccinated against rabies I was not allowed to take the animals out of the nets, all the people doing so were wearing strong leather gloves and still got bites after bites from the poor creatures, my role was to carefully take them and put each individual in a different cotton bag. After a few hours harvest was completed and we proceeded to study. Bats were carefully handed out of the bag, scrutinized, measured (some species can be told apart only by
Setting up a bat-net with Vincent
measuring the length of the forearm), biopsy taken, occasional parasitic bugs swiftly grabbed, pictures shot. All material was stored in hermetic tiny containers with alcohol, numbered and carefully disposed for later study by laboratories in order to know more about those animals. Excrement was even collected so that the genetic material of the ingested insects could be analyzed and give an idea of what insect species is hunted by this or that species of bat. On releasing the animal, tapping of their specific ultra-sounds was performed by the French number one searcher on bioacoustics part of the team. Then we could slowly make it to our hammocks for exotic nightmares!
There are of course many more animals living, roaming, hunting, eating, singing, mating and finally dying in this amazing pristine forest so we may meet some more later on, be patient!
About Jean-Jacques Segalen
I am a Parisian born professional horticulturist specialized in tropical seeds producing, living on Reunion island (just between Mauritius and Madagascar) since 20 years . I spend a lot of time gathering seeds in the wild, the ones I do not grow that is. Also a dedicated Tai-Chi practitioner and fully certified arborist-tree surgeon
Just released my first book on tropical plants and fruits, check it at http://www.barbadine.com/pages/livrejjGB.html