Marine Conservation

This Halloween’s Coolest Claws: Halloween Crabs

Why the name?

Vibrant, showy, and brilliantly bold, Halloween Crabs are named, and famed, for their colorful costumes. They have a dark brown uppercase that is often confused for black, a bright orange body and purple claws and limbs. Their eyes are a vibrant yellow, complemented by two white spots at the rear part of their carapace. Many people are taken with the crabs’ appearance and choose to make these lively creatures their pets. They are amazingly easy to handle and care for. Proper enclosure and careful measures of temperature and humidity will keep these crabs living a happy lifespan of up to ten years!halloween-crab-forblog

What are Halloween Crabs?

Crabs are unique species that can be found throughout the world’s tropical and semi-tropical regions. There are three principal groups distinguished by habitat: freshwater, semi-terrestrial and terrestrial (land).  Halloween Crabs are land crabs belonging to the Gecarcinidae family. Although they lead a terrestrial existence, at some time during adulthood, the crabs visit the sea for reproduction.


Halloween Crabs are found along river banks, mangroves, and rainforests from the Gulf of California in Mexico as far south as Colombia. Humid habitats like these provide the water sources the crabs depend on to prevent lung desiccation. As more water becomes available towards the interior of a country, the more common it is to find these crabs significantly away from the coast. For example, in Southern Costa Rica, the crab can be found up to 600 meters inland.halloween-crab-forblog2

The unique diet and behavior of Halloween Crabs is fitting of the name. Largely nocturnal, the crabs spend their nights climbing trees and burrowing in underground holes. These holes function mainly as the crabs’ store houses. The leaves and seeds of the next day’s meal are hoarded away to be kept safe and dry for these hungry Halloween crabs. While the crabs are mainly herbivorous, they can also eat fish, insects, worms, apples and other fruits and animals.


Feeling Froggy- When a professor and his favorite amphibians meet

This blog and all photos were provided by:

Steve Ressel|Professor at College of the Atlantic

This past August, I had the good fortune to visit Piro Biological Station for a few days. Piro was one stop on a seven-day scouting trip with another colleague where we explored different areas in the Osa for a future tropical ecology course. My days at Piro BioStation were few in number and mostly filled with logistical considerations associated with bringing students down to the Osa. However, I still left overwhelmed by the amount of biodiversity I saw during my brief, busy stay. I did have one thing in my favor, it was the rainy season and amphibians are my thing; the frogs did not disappoint.


TadpolesMy last day and night at the field station stands out in particular, because of the torrential rain the night before made all of the surrounding forest dripping wet for the next 24 hours . As the rain poured down, Manuel started thinking that it may be enough to prompt another round of explosive breeding in Agalynchis spurrelli (The Gliding Tree Frog) and he suggested that we head out early in the morning to see if that indeed was the case. It wasn’t, but I was blown away by the number of egg masses clinging to vegetation from previous mating bouts. Upon close inspection, I saw that many of the eggs contained well developed, squirming tadpoles.


TreeI am an avid photographer of nature and in the aftermath of the previous night’s storm, I was mesmerized all day long by the intense colors of the forest, which were hyper-saturated by the diffuse sunlight created by lingering cloud cover and a film of water on everything terrestrial. Please take me on my word that the color of these tree buttresses (Tachigali versicolor) and that of this male anole’s dewlap (Norops polylepis) were not enhanced with software.




Back at the dining area at dinnertime, I heard frogs calling at an intensity level that wasn’t evident on the previous nights of my visit. I couldn’t pass up the opportunity to explore with my ears and eyes. So, with some suggested field sites from Manuel and Renee, I set out into the night with my camera and headlamp. The first stop was along the banks of Piro River to look for glass frogs. I heard them calling in the overhead foliage but the tadpolespersistent wet conditions did not stimulate them to descend within reach of my camera’s lens. However, I could see that there were numerous egg masses of Cochranella granulosa (Grainy Cochran Frog) that were deposited some time before my arrival. Like The Gliding Tree Frog eggs I saw during the day, many of these masses, like the one pictured below, were “ripe” with very active tadpoles.





I was then drawn to standing water, by the call of a frog that I was hearing for the first time during my visit. After a little searching, I discovered it was Scinax elaeochroa (Sipurio Snouted Tree Frog) that I was hearing and now seeing for the first time ever. 


Look at those coppery eyes!





There was another species calling alongside S. elaeochroa and I knew it well. It was Dendropsophus ebraccata (The Hourglass Treefrog), that I studied in Panama while in graduate school, and their abundance that night was staggering. My mind flashed back to 1992 when I spent many wet, warm nights studying the biology of this frog because of its impressive capacity for calling. Fast-forward to the present, I was now focusing on the multitude of D. ebraccata around me because they are just so damn photogenic.

tree frog

The Hourglass Treefrog


I went to bed that night – or rather, early the next morning – reluctantly because, for the frogs, the night was still young. My hope is that in the near future, I can share these amphibian experiences with students. Although, I must confess that as I drifted off to sleep, I relished the fact that I had the frogs to myself that night.





Stay tuned for 2017 courses with Professor Ressel!


Sea Turtle Patrol on Pejeperro Beach

A blog entry by Vedant Jain (University of California Berkeley)

Hi folks or should I say Pura Vida! Here is a little snippet of one of the adventures we had here. On Wednesday morning, after a nice late start we headed to the Piro station where we met with Manuel Sanchez who gave us an introduction to the four species of local sea turtles and the sea turtle conservation efforts on the Osa Peninsula. Turtle conservation is especially important because sea turtle eggs face dangers from factors such as predators, tidal changes, and especially egg poachers. Manuel explained how different turtles come to Costa Rica at different times to lay eggs. July it turns out is an ideal time for both Olive Ridley Sea Turtles and Green Sea Turtles. We returned to camp ready for our first turtle patrol!


Osa Conservation does turtle patrols at night and in the early morning, relocating nests of turtles laid in dangerous conditions to their 2016 hatchery, or vivero in Spanish (photo by Lara Bogdanovich)


Relocated Olive Ridley nests in the sea turtle hatchery (photo by Ross Kamimoto)

At 8 pm we joined Manuel and hiked to the Pejeperro beach for our night patrol. Manuel explained that the best way of seeing animals at night is to look for eye glow. This is the light reflected when you shine a flashlight into an eye. With this knowledge Manuel helped us spot birds, frogs and crown jewel of them all an ocelot!



Manuel (right) wraps headlamps in red cellophane before beginning our night patrol (photo by Fernando Iglesias)

When we finally arrived on the beach it was honestly like a dream. The clouds had cleared up and the sky was cascaded with stars. Each one glowing with the bright illumination that you can only get without light pollution. When you took a step on the sand it would spring to life with its own vivid color, the bioluminescence complementing the light of the skies. In the background the waves crashed with perfect rhythm, a symphony of their own. It was a beautiful juxtaposition of earth, sea, and sky.

We began walking down the beach. We covered our flashlights with red cellophane because white light can scare the turtles into leaving without laying eggs. Eventually we turned off our flashlights completely, the stars providing more than enough light.

Finally, Manuel tells us to stop and he walks on ahead, he says he saw something. He gestures to come over. There hidden just below sand level is a 65 cm long female Olive Ridley laying her eggs. They say that when a turtle is laying eggs she enters almost a lucid dreaming state, whereby she never realizes that we have seen her. Manuel explains how he puts tags on every turtle they find to keep track of them. We watch as he gets the turtle ready but is unable to put the tag on because the tagging mechanism had a broken part.


The nesting turtle returning to the sea (photo by Ross Kamimoto)


Aluminum tag used to mark nesting sea turtles by Osa Conservation (photo by Ross Kamimoto)

Sitting there next to the turtle I feel like I am witnessing an ancient ritual. Turtles are some of the oldest species dating back almost 125 million years. In that moment I felt so small and insignificant to the enormity of life.


A poem by student Lara Bogdanovich about the night patrol


It’s true we carry the world inside us,

Always present like light

Or instead fleeting like galaxies in the grain

Stirred and strong by inertia


There is a narrowing absorption of the sky

So saturated it can yield no more

It shivers as eyes move across it

Like a flexible blade.

Then end circulates in the wide space of summer

Here we have what lasts;

And the soft perishable mind which doesn’t.

The end circulates in the wide space of summer

Where everything began

And goes on beginning.


A big thank you to Round River for the opportunity given to these small groups of students from study abroad programs who have the chance to experience and learn by participating in awesome field trips.


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