Over the past several weeks, many people across Colombia's Caribbean region have been saying the same thing: It feels hotter than usual. The average temperature for the month of May was 34°C (93.2°F ). Weather forecasts have even suggested the possible development of a new El Niño event, which is often associated with drier and warmer conditions throughout much of the country. While many of us notice these changes when we step outside, the cotton-top tamarins living in the tropical dry forests of northern Colombia are experiencing them as well.
At Proyecto Tití, we have been monitoring climate conditions in our conservation areas for decades. At Reserva Los Titíes de Ceibal, we have maintained continuous climate records since 1999, and at our San Juan Nepomuceno field site since 2022. These long-term datasets provide an invaluable window into how environmental conditions change over time and how forests and wildlife respond to those changes. The most recent monitoring data reveal a concerning trend. In May 2026, our weather stations recorded just 0.4 mm of rainfall across only two rainy days—one of the lowest precipitation totals observed for this time of year. By comparison, May 2025 received 167.8 mm of rain over 13 rainy days. At the same time, average temperatures in May 2026 were nearly 1°C (1.8°F) higher than during the same period the previous year. A one-degree increase may not sound significant.
After all, most of us can adjust our thermostat by a degree and hardly notice the difference. But for wildlife already living in temperatures that regularly reach the 90s°F, even a small rise in temperature can have serious consequences. Unlike humans, cotton-top tamarins cannot escape to air-conditioned buildings when temperatures soar. Instead, they depend on behavioral adaptations and the cooling benefits of healthy forests to help them cope with heat stress.
Our field teams have already begun observing changes in the tamarins' daily activities. During the hottest hours of the day, it is increasingly common to see cotton-top tamarins resting on branches in what researchers refer to as a "cooling posture." Rather than sitting upright, the tamarins stretch out along the length of a branch, increasing the amount of their body that comes into contact with the cooler surface. This simple adjustment helps dissipate excess body heat and allows them to regulate their temperature more effectively. The tamarins are also modifying how they spend their time. During periods of extreme heat, they reduce their movement and activity levels.
By remaining more still, they conserve energy and avoid generating additional body heat through physical exertion. This strategy helps them maintain a safe body temperature while minimizing physiological stress.
These behavioral changes are remarkable examples of adaptation in action. They demonstrate the resilience of cotton-top tamarins and their ability to respond to changing environmental conditions. However, adaptation has limits. The ability of cotton-top tamarins to cope with increasing temperatures depends heavily on the availability of healthy forest habitat. Forests provide shade that can significantly reduce temperatures beneath the canopy. They also offer access to food resources, shelter, and moisture during periods of drought and extreme heat. When forests are fragmented or degraded, wildlife loses many of the natural protections that help buffer the impacts of climate change.
This is one of the reasons Proyecto Tití's conservation efforts are so important. Our work focuses on three interconnected goals: protecting existing forests, connecting fragmented habitats, and restoring degraded areas to create more forest for cotton-top tamarins and other wildlife. These efforts not only help preserve biodiversity but also strengthen the resilience of ecosystems in the face of a changing climate.
Climate monitoring is another critical component of our conservation strategy. By collecting long-term environmental data, we can identify trends, understand how wildlife responds to changing conditions, and make informed decisions about conservation actions. These data help us move beyond observations and anecdotes, providing scientific evidence that guides our efforts and helps us prepare for future challenges. The information we gather is becoming increasingly important as climate change continues to reshape ecosystems around the world. Understanding how species respond today allows us to better anticipate what they may face tomorrow.
For cotton-top tamarins, the future will depend not only on their ability to adapt but also on our commitment to protecting the forests they call home. Every forest corridor we establish, every hectare of habitat we protect, and every tree we plant contributes to a more resilient future. Healthy forests help moderate temperatures, retain water, support wildlife populations, and provide benefits to local communities as well. The challenges posed by climate change can feel overwhelming, but they also remind us why conservation matters. Protecting forests is not just about saving a single species. It is about safeguarding entire ecosystems and ensuring that both people and wildlife have the resources they need to thrive in an uncertain future. The challenges posed by climate change can feel overwhelming, but they also remind us why conservation matters.
Protecting forests is not just about saving a single species. It is about safeguarding entire ecosystems and ensuring that both people and wildlife have the resources they need to thrive in an uncertain future. The cotton-top tamarins are showing us how they respond to a warming world. By continuing to monitor climate conditions, support scientific research, and protect critical habitat, we can help ensure that these critically endangered primates have the opportunity to adapt and survive. Because when the forests are healthy, the tamarins—and the communities that share their landscape—are better equipped to face whatever challenges lie ahead.