For nearly two years, a wild sloth called Pistachio quietly contributed to one of the most detailed studies of urban sloth life. Now his collar has come off and his job as a research sloth is over.
The Sloth Conservation Foundation reported in its October 2026 field update that Pistachio had retired from the Urban Sloth Project after 22 months of tracking. He was one of the project's longest-running residents and had become known as the coffee shop sloth.
Retirement sounds like a human idea, especially for an animal that never applied for a job. In wildlife research, though, it describes something important: a planned end to monitoring. A collar is removed, the animal returns to life without research equipment, and scientists keep working with the information already collected.
A collar turns one sighting into a story
Spotting a sloth once can tell researchers where that animal was at one moment. Following the same individual over many months can reveal routes, resting places, daily rhythms and changes that a short visit would miss.
The Urban Sloth Project is a long-term investigation into how habitat disturbance and urbanisation affect wild sloths in Costa Rica. Some monitored animals live in primary rainforest, while others navigate towns where trees are mixed with roads, roofs, fences, gardens and power lines.
That comparison matters because an urban sloth is not simply a forest sloth with buildings in the background. Gaps in the canopy can alter where an animal travels. Roads may force risky ground crossings. Small patches of shade can become important places for managing body temperature. Researchers need repeated observations to see which patterns are normal, which vary between individuals and which may be linked to the landscape.
What the equipment records
Sloth tracking has changed as the technology has improved. The foundation's guide to collars, backpacks and data loggers explains that VHF collars emit radio signals that help a field team locate an animal. GPS collars can add location points, while tiny data loggers and accelerometers can record movement, position and environmental information.
The clever part is not simply collecting a dot on a map. Movement traces can help researchers distinguish activity from stillness, examine when an animal moves, and connect behaviour with temperature or habitat features. Field observations remain vital because a machine cannot explain every event by itself.
Equipment also has limits. Signals stop, batteries run down, dense vegetation interferes with reception and a collar may need replacing. The same October update says the team found another sloth, Flash, after his old collar stopped transmitting and fitted a replacement. A silent device does not automatically mean something has happened to the animal.
Why 22 months can matter
Pistachio's 22 months of monitoring can capture far more variation than a brief study. Wet and dry periods change. Food trees flower and produce new leaves. Construction, traffic and canopy routes may alter. The sloth itself may shift its habits or home range.
One animal cannot represent every sloth, but individual records become powerful when researchers compare them carefully. In September 2026, the project shared preliminary results from 49 tracked sloths and 31,819 hours of behavioural data. The team stressed that the work was still ongoing and that observed differences should not be turned into confident explanations too early.
That caution is part of good science. Pistachio's record is a detailed chapter, not the whole book. It can be combined with data from many other two-fingered and three-fingered sloths, different habitats and different seasons.
Research should have a finish line
A tracking collar is a scientific tool, not a permanent badge. The foundation says its collars are lightweight, fitted for the individual and used temporarily for a defined research period. Removing Pistachio's collar after a long contribution makes that endpoint visible.
Ethical field research asks whether the knowledge gained is worth the intervention required. It also asks whether equipment is suitable, how animals will be monitored, when devices should be checked or removed, and what happens if a signal fails. Those questions are just as important as the charts produced later.
Retirement does not mean Pistachio leaves the rainforest or enters human care. Based on the foundation's update, it means he leaves the research project. He continues being a wild sloth while the data from his tracked months continues to teach people about urban sloth life.
From one sloth to safer habitat
The larger purpose of the Urban Sloth Project is practical conservation. Tracking can highlight frequently used trees, dangerous crossings and places where canopy connections are missing. That evidence can guide native-tree planting, wildlife bridges and conversations with the people who manage roads, power infrastructure and neighbouring land.
Pistachio may never know what his thousands of data points mean. That is fine. His part was simply to live his ordinary sloth life while researchers listened carefully from a respectful distance.
After 22 months, taking the collar off is not the end of the story. It is the moment the fieldwork gives way to analysis, conservation decisions and, for Pistachio, life beyond the dataset.
Sources
- The Sloth Conservation Foundation: Tales from the Jungle, October 2026
- The Sloth Conservation Foundation: The Urban Sloth Project
- The Sloth Conservation Foundation: Collars, Backpacks and Data Loggers
- The Sloth Conservation Foundation: Preliminary Urban Sloth Project Findings
Featured image: Pistachio during the Urban Sloth Project. Credit: The Sloth Conservation Foundation.