Luna: Her Illuminating Legacy

Luna: Her Illuminating Legacy


Luna made an unexpected entrance into the Urban Sloth Project (USP) in March 2021, accompanied by her first baby, Sol. Over the course of 24 months, Luna emerged as a key figure in our research, capturing our attention like no other sloth we had studied before.



Her charismatic nature drew a large following within our community, with people eagerly awaiting updates on her remarkable adventures. In this blog, we will reflect on the incredible years we spent monitoring Luna, her offspring, and the final days of her journey.


When we found Luna

The area where Luna was found is a hotspot for sloth and wildlife spotters. Groups of tourists huddled excitedly together with their phones and cameras out is almost a guaranteed sign of sloth action. This is precisely what caught SloCo founder Dr. Rebecca Cliffe’s eye as she drove along the winding beach road after lunch one day, and she was right: a sloth was trying to cross the busy road.



Dr. Cliffe stood in the road to block oncoming traffic, helping Luna make her way slowly and safely across the road. On closer inspection, she noticed a tiny baby clinging tightly onto the fur on Luna’s back!


sloths on the ground mom and baby


Dr. Cliffe quickly realized that this duo would make a fantastic addition to our Urban Sloth Project, so she immediately called Ecology Coordinator, Amelia Symeou, to rush over with the collaring and tracking equipment.


baby sloth luna sol

They collected important measurements such as body length, arm span, and finger/toe length and took the combined weight of both mom and baby. The team didn’t want to unnecessarily stress the pair out by trying to separate them to get individual measurements, so everything happened while Sol was clinging tightly to Luna’s stomach.

Sol, the first baby of Luna (and the USP)

Sol was our very first baby of the project, and we were privileged enough to watch him grow and eventually gain his independence from Luna! Inspired by the moon, we named Luna, while the sun inspired us to name her baby Sol.


Baby Sol


In October 2021, the Tracking Team observed Sol entering his rebellious teenage phase. He sought distance from his mother and longed to explore on his own. Initially, he clung onto Luna’s fur with three limbs instead of four, gradually shifting to gripping a vine. Eventually, Sol was spotted beside Luna instead of on her.




We had hopes of collaring Sol once he was independent, but he had other ideas! One day, he ventured out on his own, no longer seen with Luna, and we could not identify him from the many other male sloths in the area. Luna graciously granted Sol a portion of her territory, marking his official transition into adulthood.


Trees cut down and habitat disturbance

Shortly before Christmas of that year, Luna’s territory faced a partial illegal deforestation, leaving numerous sloths and countless other wildlife without a home.



However, the community refused to remain passive in the face of this crisis. Determined individuals and local organizations, including SloCo, took action and reached out to the Costa Rican government’s environmental agency, who possessed the authority to permanently halt the planned development.


The community of Puerto Viejo came together to stop habitat loss


Celeste, her second baby!


Despite the devastation of Luna’s habitat just a month previously, in January of 2022, we were delighted to spot Luna and her new baby! The name Celeste symbolizes the light blue shade of the sky and continues our aerial-name theme.

A week prior to the deforestation, Luna disappeared into the highest trees of an area previously unexplored to her, sans baby. It is not possible to tell if a sloth is pregnant without an ultrasound – their bodies do not change much due to their impressive rib cage, and any extra weight can be explained by their toilet routine.



When the deforestation occurred dozens of sloths were displaced. While we were there assessing the damage, we were keeping an eye out for Luna, who we could identify by her collar. As we were watching the displaced sloths, we noticed a mom and baby. Looking closer, the mom had a collar! Surprise! Luna had given birth to her second baby, Celeste.

They crawled their way through the wreckage of trees in their territory, eventually finding a tree to ascend to the safety of the canopy. Over the following months, Luna lovingly raised the adorable baby Celeste. As the weeks went by other females in the area began to give birth, and they often shared their trees with Luna and Celeste, making a baby sloth creche up in the trees!


Can you spot the antenna?


Unlike Sol, we didn’t witness Celeste gradually exploring the branches near Luna. Celeste would climb all over Luna instead of the nearby branches. In August, when Celeste was around seven months old, she was no longer seen with her mother. Around the same time, we observed Luna engaging in mating behavior with males in the area. During that month, we caught sight of a small sloth in the nearby trees, which we suspected was Celeste.

The star of the second International Sloth Festival

In October 2022, Luna gained even more popularity during our Festival, which took place just a few meters away from her home. As part of the festival activities, we organized sloth tracking sessions for groups, families, and children, providing them with the opportunity to experience the life of a sloth scientist firsthand.


sloth fest 2022


Luna, as always, remained our trusted companion, captivating the hearts of visitors as they listened eagerly to her story and that of her babies. It was during this month that we achieved a milestone of 250 tracking sessions with Luna!



Eclipse, Luna’s final offspring, received a name inspired by astronomical phenomena, following the tradition set by his mother and siblings. We first caught sight of Eclipse in February 2023. Interestingly, the exact gestation period of three-fingered sloths remains unknown, but we estimate it to be around six months based on our observations of Luna being without Celeste and engaging in mating behavior with males.


Luna and her broken arm

On March 12th, 2023, we spotted Luna climbing a tree using only one arm, the other hanging uselessly by her side. Without hesitation, we sprang into action, rescuing Luna and swiftly arranging her care with a local rescue center.



We don’t know how Luna broke her arm. It is common for sloths to fall from trees, and their anatomy is designed to survive falls onto the jungle floor. With no accompanying injuries to indicate she had been attacked by another animal or hit by a car, the most likely explanation is that she fell and landed badly on a rock or some of the coral on the seaside edge of her territory.



Sadly, Eclipse did not make it. We don’t know if Little Eclipse was injured in the fall or if Luna’s body stopped producing milk after her injury, and she could not sustain her baby. We are heartbroken over little Ecplise; the little one was only a few weeks old but will remain in our memories.

Surgery and post-op

It took us three days to organize the surgery to fix Luna’s arm, but with help from the local rescue center, vets, and our generous donors, we were able to arrange for a specialized orthopedic surgeon to come from San Jose (the capital of Costa Rica) to our little town to perform surgery on Luna and save her arm. The hour-long surgery where Luna’s fractured humerus was reset with titanium plates was an initial success.



We were also thrilled to reaffirm, once again, the love, support, and commitment of our wonderful sloth community, who responded immediately with donations for her surgery as soon as we made the call on social media.



Luna was showing promising progress since her surgery. We knew that her journey to full recovery would be complicated, but we held onto hope that she would make it through.

Luna’s farewell

Unfortunately, Luna’s passing came as a sudden and unexpected shock. It pains us to say that this is not an uncommon occurrence with three-fingered sloths, as they are incredibly delicate creatures and pose unique difficulties when it comes to treatment, making them one of the most challenging species to care for in rescue centers. Luna was in the best possible place to be cared for, as this rescue center is one of the only places to successfully care for three-fingered sloths.

Despite the tireless efforts of the dedicated veterinarians, Luna’s sudden departure has left us in disbelief and utterly heartbroken. Finding the right words to convey this devastating news to our community and supporters has been difficult, as we know how many people out there held a special place in their hearts for Luna.

One of the most special sloths

Luna was a remarkable sloth for so many reasons. While we monitored her, she gave birth to three beautiful babies, and she was an integral part of our research, providing us with invaluable data about the lives of sloths living in urban environments. Luna’s memory will forever remain in our hearts and in the essence of the Urban Sloth Project.



In the coming years, we will continue to analyze the data she has provided, which may appear as mere numbers, but will offer profound insights into her personality, preferences, and daily life. Luna’s legacy will continue to benefit other sloths like her.



To all those who adopted Luna or generously contributed to her surgery and treatment, we extend our deepest gratitude. Your unwavering support during these challenging times has been truly remarkable. Once again, we thank you from the bottom of our hearts for standing by Luna and our cause.


-Amelia Symeou

Ecology Coordinator/USP

-Cecilia Pamich

Communications & Outreach 


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