Until now we have seen 31 species and made specimens out of 24 of these 31 species. We are doing this to make a collection of animals in this area to improve the knowledge on the species in this area. And also of course to teach us where work in the field really is about. This involves not only searching of the animals in the forest, but also fixing the animals in a way that they won’t degrade so that they can be studied indefinitely. The collection of animals and also voucher animals have 3 important purposes. i) Species identification allows correct identification of species, ii) allows studying of intraspecific variation iii) confirmation of occurance of a species in a certain area. I hereby will explain the steps of fixing herps, and yes sadly this involves killing your specimens. Its sad, but for science! In the end it could make conservation easier by learning more about these beautiful creatures.
There are 6 steps involved into fixing an individual:
1). Prepare formaline. You do this by adding water to formaline powder. A good percentage of formaline to water is 10%.
2). Chytid swabbing – only for amphibians. Chytridiosmycose is a disease which is very widespread and thought to cause a high mortality on numerous amphibian populations around the world. The disease is caused by a chytrid fungus with the name Batrachochytrium dendrobatidis. In order to prevent this disease or learn about the prevalence and more we sample by making skin swabs. This should normally been done directly in the field, however we did this in the lab at the field station. The method we used is 5 swabbings on the following regions: ventrally, thigh, feet and hand. You leave the quetip in a tube which can be later analyzed if the sample indeed contains the fungus. Much like how saliva sampling works in human DNA analysis.
3). Take photo’s – we do this while the animals are still alive because some animals can lose their colors. With photo’s it will always be possible to see some characters in the state of the live form.
4). Kill – We kill by using anesthetics: Lidocain 2%. Amphibians can be killed by putting them in the substance, while bigger amphibians and lizards should be injected with a needle and syringe with this substance.
5). Taking tissues. Avoid to take liver samples. This has been done in the past. However, the liver has a lot of waste product. A good alternative are muscles cells from the legs. Use tweezers and a sharp scapel, clean this with ethanol between procedures and burn to clean it completely. Burning can be performed with a lighter. Take a muscle sample at the thighs, in snakes you could use a sample between the ribs and in some small lizards we could use the liver.
6). Fixing – We fix the animals with the formaline. You use a tray with a paper towel with formaline to put the animals on top of it. You can modify the position of the animal. Eventually you cover all animals in the tray with paper towels drenched in formaline. The formaline results in hardening or stiffening of the animals. Eventually you will have animals that have nice positions to look at characters. For example, it is wise to fix a frog with its feet wide open so its easy to describe the webbing and other characters. Big animals should be additionally injected with formaline to prevent degradation. The whole tray should be kept in the shadow and should be closed with a lit to prevent evaporation.
The result of the fixing process can be seen in the photo. I also would like to point out that Philipe normally does this work alone or with a partner. It can take a lot of time to prepare you specimens this way. Luckily we are with 7 and we could form a production band which speeded up the process.
Later this day, in the evening, we did some extra additional awesome herping! After the evening dinner, which again was terrific, we left for a boattrip on the Essequito river. We weren’t on the water for a minute and we could already spot two caimans. Simon, our ranger guide, found a snake shortly after that on a twig. I need to inform you that it incredibly difficult to see in the dark with just a headlamp. The banks of the river are filled with trees and other vegetation which make the whole searching for herps a big “Where is wally” game. However, the extra added difficulty is the darkness. Philipe caught the snake, a Corallus hortulanus, professionally with the tong. We weren’t even back in the boat for longer than five minutes and Simon already saw another incredible specimen. This was one was rather high on the tree which hung over the water. Nothing could stop our ranger when he climbed into the tree to get us that snake. Simon climbed and fought against all different obstacles. Pointy needles and stinging ants all over the tree. Simon was though and managed to get the snake down. Which resulted in the second catch of the day.
Another objective was to catch a small caiman. Again, Simon spotted various caimans from a large distance. This is quite easy if they are in the water because of the reflection of light by the retina if you shine upon an animal. The caiman, was not that large and Philipe got it with the tong. However it slipped away and climbed through spiny vegetation on the steep river bank. Two of our rangers went out of the boats and climbed up. After a while one of the rangers located the caiman up on the hill and managed to grab it resulting in the catch of a caiman! Incredebly excited with the catch we went on until we came to a sandbank in the river. After some Hypsiboas and Rhinella marina catching (a quite large one I must say) we saw another small caiman, but larger as the previous one. Philipe used all his skills. He followed the caiman, and plunged in the water. The caiman splashed and swum away, however Philipe jumped again to the caiman. He landed standing half way in water on all fours, sadly, the caiman swum away as fast as he could by using its mighty tail. Nonetheless, the evening was perfect, we finally caught two snakes and even more special, a caiman! Tomorrow will be an exciting day. After breakfast, putting tags on our fixed specimens and making photo’s of the caught individuals of toning we will do something I have never done before! Tomorrow will be the day when we will go into the forest and sleep there for a few days in our hammocks. The real survival days are about to come and I’m nervous, but excited!