Archive | April, 2012

Sloths: a Misunderstanding

19 Apr

Sloths are an oft-misunderstood species.  Despite moving slowly and appearing to sleep all day, the life of a sloth can be quite compelling.  Sloths are masters of camouflage; they hide in plain sight despite being hunted by the most vicious predators in the jungle.  And let’s face it – how many times have you been in a resort in Cahuita, Costa Rica and had a sloth just appear, as though out of thin air?  Not only are sloths masters of stealth, but they are quite intelligent.  Many of the sloths at the Sloth Rescue Center in Costa Rica spent their youths finding ways out of their containers.  Our visit to the rescue center explained – sometimes in song – the simple dignity of these animals, and the complexity behind their behavior.

Species

There are currently six sloth species belonging to two different families: Bradypodidae (three-toed sloth) and the Megalonychidae (two-toed sloth).  However, the distinction between two and three toed sloths is inaccurate as all sloths have three toes.  The difference is only present on the species’ fingers.  Only the Hoffman’s Two-fingered sloth (Choloepus hoffmanni) and the Brown-throated sloth (Bradypus variegatus) are found in Costa Rica.  Neither is considered endangered, however two species not found in Costa Rica, Bradypus torquatus and B. pygmaeus, do receive protection.

Ground sloths have gone extinct relatively recently.  These sloths could grow up to 20 feet in length and would feed by pulling entire branches from the trees.  However, these sloths had none of the adaptions that allowed their modern counterparts success in their environments.

Sloths belong to the order Pilosa.  Therefore, they are most closely related to armadillos and anteaters.

Habitat

Sloths are arboreal, and very rarely leave their tree.  They are indigenous to the rainforests of Central and South America.  They are either diurnal or nocturnal.  Sloths are also proficient swimmers, which is instrumental for survival during the rainy season.

Arboreal.

Diet

Sloths each leaves, shoots, and buds.  However, sloths have been observed complementing their diet with insects and small birds.

Predators

The harpy eagle, jaguars, and humans pose the largest threat to sloths.  While harpy eagle and jaguar related fatalities are difficult to document in the jungle, most sloth deaths are believed to be human inflicted.  While sloths are tough in their natural environment, such as being able to withstand falls from the canopy, many succumb to the dangers provided by deforestation and human development.  Many sloths at the rescue center were victims of electrical burns from power lines or lacerations from barbed wire fences.  Sloths are natural climbers and are unable to differentiate between a human imposed danger and their own habitat.

Adaptations

The sloth has many adaptions suitable for living in a tropical climate.  Their claws are strong enough to support the weight of a hanging sloth even after its death.  The claws are also utilized for territorial disputes between the males.

Other adaptions allow the largely defenseless sloths to escape predation.  The bradypus has nine vertebrates that allow a full 180 degree range of motion of the head.  Therefore, this sloth can detect whether an aerial – harpy eagle – or ground – jaguar – threat is imminent.  The sloth has also formed a symbiotic relationship with cyanobacteria.  These algae assist in camouflage by forming green spots on the sloth’s fur.

Sloths also have an incredibly slow metabolism to complement their lifestyle and diets.  Leaves offer little nutritents and are difficult to digest.  Therefore, it can take a sloth upwards of one month to digest a single meal!  The sloth has a multichambered stomach and has formed a relationship with symbiotic bacteria to assist in the digestion of leaf material.  About once a week the sloth exits the tree to use the bathroom.  By going so infrequently, the sloth minimizes the time away from the tree, when they are most vulnerable.  Sloths also have a very low body temperature for mammals, diverting much of their energy to digestion.  While the term sloth is synonomous with being lazy, recent studies have determined that sloths in the wild only sleep about ten hours per day.

Other Fun Facts

Sloths are solitary animals.  Adult sloths only interact to mate or dispute over mating or territory.  However, in the sanctuary sloths can become social if paired with a single other companion from a young age.

It's just unnatural

Sloth reproductive organs are protected by the rib cage.  Therefore, determining the sex of a sloth in the wild is nearly impossible.  This led to problems in the sanctuary, as some sloths were misnamed or reproduced with their companion – all without their caretakers knowing it was possible!

Rescue Center Facts

The Sloth Rescue Center in Costa Rica originally began as a bed and breakfast.  A singular baby sloth was brought to the future rescue center over twenty years ago.  Now, the facility is home to over 130 sloths.  While the center attempts to reintroduce these sloths into the wild every year, there are many limitations that prevent their efforts.  Many sloths are too injured to climb trees.  Sloths that were brought in as babies cannot be reintroduced into the wild.  In the wild, infant sloths cling to their mother’s fur while she teaches the infant which plants are nontoxic.  Without such teaching, the sloths must remain in the sanctuary for the entirety of their lives.

The rescue center is nonprofit, and relies on tours and donations to cover its operating expenses.  There is no government agency that is responsible for the collection of injured sloths.  Therefore, a large local effort is required for this institution to survive.  Many of their refugees were passed along from concerned citizen to concerned citizen until they reached the sanctuary.  Unfortunately, many sloths do not survive this journey.

The sloth sanctuary is thriving.  The original sloth, Buttercup, still resides at the rescue and is now the oldest surviving sloth in capture in the entire world.  Wild sloths attempt to scale into the sanctuary to meet the resident female population protected there.  Ultimately, centers such as this one can mitigate some of the harm that development has inflicted on indigenous species.

Briggs, Helen (2008-05-13). “Article “Sloth’s Lazy Image ‘A Myth'””. BBC News. http://news.bbc.co.uk/2/hi/science/nature/7396356.stm. Retrieved 2010-05-21.

http://www.slothrescue.org/?f

http://www.slothsanctuary.com

http://en.wikipedia.org/wiki/Sloth

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Murcielagos (Bats)

16 Apr

Myths

When people think about bats, they often think about frightening images: vampires, Halloween, Dracula… Even one positive popular image associated to bats – the superhero Batman – has a dark side.

Another popular, and scary, myth about bats is that of El Chupacabra – a Latin American legend of a batlike creature that killed livestock such as goats by sucking their blood. This is one of the most gruesome and also unrealistic ideas associated with bats.

First of all, the size and features of El Chupacabra are greatly exaggerated in comparison to what real vampire bats (the ones that suck blood) look like.  Vampire bats get their name because they suck animal blood in order to survive, but never enough to kill the animal.  All vampire bats, not just the El Chupacabra, are however considered pests to farmers though because they can spread diseases to their cattle by leaving open wounds which are prone to infection.  Unaware farmers may kill any type of bats in order to protect their livestock because they view all bats as threats due to a lack of education about bats.

These myths have ruined the reputation of bats.  Many people do not like them, without good reason. So the goal of programs like the Conservation Association of Monteverde, Costa RICA (ACMCR — http://www.acmcr.org/) is to educate people of all ages to the truth about bats and to show them the benefits that these mammals bring to our environment so that we can all see why they should be not only appreciated for what they are, but conserved as well.

The bats didnt always have such a bad rep: The ancient Mayans and Aztecs worshiped bats as gods! Clearly they saw some good in these animals.

Reality about Bats

Bats are mammals (they have fur and they produce milk) – just like us!  They are one of the most common species of mammals as well.  Of the 5416 species of mammals worldwide, 21% (1116 species) are bats.  In Costa Rica, there are 113 species of bats.

Anatomy

Though they have wings, bats still maintain five fingers.  This is one piece of evidence that humans and bats are still pretty closely related evolutionarily.

Another myth about bats is that they are blind. The reality is they actually can see, but they are colorblind and their vision is relatively poor.  Because their vision is not great, bats rely mostly on a different method to “see”.  Bats use echolocation, an ability quite like sonar.  They emit high frequency calls and then listen to the echos in order to locate objects around them (such as their prey).  Some bats use their mouths to transmit the sounds, while others use a unique body part called the nose leaf.  Most bats have large ears to help them receive the sounds that are bouncing back. Bats can form 100 images per minute using this echolocation.

Where they live

Bats make their homes in a variety of different places: in caves or mines, under fallen trees, in hollow trees, in abandoned termite nests, in rolled up leaves (these bats have suction disks on their limbs to keep them from falling out), and in “camping tents” — the leaves are folded over and chewed to form a tent-like shape.

Diet

Bats have a varied diet, and you can usually tell what they eat by looking at their facial structures.  There are general rules that can help identitfy them, although these rules that follow only apply in Costa Rica:

  • Bats that eat fruit have a big nose leaf
  • Bats that are carnivorous have large ears
  • Bats that eat flying insects have tiny eyes
  • Bats that eat fish look like bulldogs
  • Bats that eat nectar have a long snout and long tongues
  • Bats that suck the blood from cows and other large mammals have flat noses, sharp front teeth, and a split lower lip

Environmental Benefits of Bats

Bats eat insects that we consider pests.  A 10 gram bat eats 1000 mosquitoes per hour! This means people can save a lot of money on pesticides and not get bitten as often.

Bats also aid in seed dispersal for some species of plants.  For example, A 20 gram short-tailed bat eats Cecropia seeds and disperses 24,000 seedlings per night! Bats are well known for helping regenerate forest due to their seed dispersal.

Nectar eating bats pollinate flowers. Most importantly, bats are the pollinator of the agave plant – which we use to make tequila!!

Conservation

Groups like ACMCR are working to conserve bats.  At the Tirimbina Biological Reserve in La Virgen de Sarapiquí, Heredia, Costa Rica they research the abundance and diversity of bats as well as educate people (starting with young children) to eliminate the bad reputation that bats hold.  In order to study the bats, they use nets to catch them. The main reason that the bats fall into the net traps is because they turn off their echolocation from time to time to save energy and they unknowingly fly into the nets. The two species that were caught the night we went to the reserve were the Little black myotis – Myotis nigricans:

bat pic 2

and the Central American yellow bat – Rhogeessa tumida:

We also saw some bats on a boat tour we took down the river; these bats were called the “long nosed” bat (Rhynchonocteris naso)

 

Source:

http://www.tirimbina.org/ecotourism/bats-program.html

Mi Cafecito

16 Apr

Introduction

Mi Cafecita is a coffee plantation located in the high zones of San Carlos and Sarapiqui. It is 900 meter above sea level in elevation. It is a cooperative consisting of 137 small coffee producers. The coffee production is focused on Fair Trade principles and sustainable agriculture. The cooperative produces coffee for both domestic and international sales. They also offer tours and sell coffee and food on sight to attract business. Our class visited the facility and took the tour guided by Walter. We learned about each step of the coffee making process and were able to sample some of the fine product.

This is our tour guide, Walter

History and Social Impact

The cooperative started with a group of 40 coffee farmers in 1969. They came together and pooled resources to ensure their success and promote “spirit of mutual help in economic, social and cultural matters”. They adopted the title of Coopesarapiqui and Mi Cafecita coffee tours soon followed. It has also stood for clean and sustainable environmental practices.

This mural depicts how coffee plantations began in the 1800's

In addition to being a business the cooperative ensures that its members are taken care of. They also participate in restructuring and other social good projects. These include activities related to the crops themselves, modernization of agriculture practices and advanced marketing techniques. The cooperative is also dedicated to promoting the highest quality of environmental efficiency and places high merit on pollution prevention and implementation of the cleanest technologies without sacrificing quality or the needs of its members.

Coffee Production

The coffee plantations are located around 800 to 1000 meters above sea level, as is standard in Central America. It is grown in a tradition of their ancestors

This a freshly husked bean in a warm and welcoming hand

and stresses low acidity in order to produce first quality coffee that does not harm human health. The seedlings are rooted under a canopy for a few months and then planted in the soil. After a few years the plants are ready for harvest. Once the berries are harvested, they can then be removed from their husk and then sorted using a water based technique. The first quality beans naturally make better coffee which can be sold at a higher premium. Next, the beans are dried either in a greenhouse or an oven. The second skin layer is then removed and the coffee beans are ready for export. They do not roast the beans on site because the coffee is better when the beans are more freshly roasted and they have a longer shelf life.

This is greenhouse where the coffee beans are dried

Ecotourism

The view from the scenic overlook

In addition to being a coffee plantation, Coopesarapiqui offers tours of its land and facilities, and birdwatching. Each highlight the land’s natural beauty. Our guided tour not only took us to some coffee plants, but also to some spectacular views of the Sarapiqui and Maria Aguilar Rivers and their surroundings. We saw a breathtaking valley and walked through some of the hills near the plantation where we saw a beautiful waterfall and scenic overlook.

The picturesque waterfall we viewed on the Sarapiqui river

Jack with a machete