In 1982 a husband and wife began recording mammals along fixed trails on an island in the Panama Canal, later adding a line of camera traps, and they kept it up for 44 years. This year they began handing the project to a younger researcher who wants it to reach 100 years.

Two things happened, 44 years apart, on the same forested island in the middle of the Panama Canal. In 1982, a married pair of researchers started walking a fixed set of trails once a year, writing down every mammal they saw and how common it was. In 2026, a younger researcher took the lead, aiming for something none of them will live to see: to keep the count going until it reaches a full century.

It is worth slowing down on this, because projects that outlast the people who start them are rare, and the ones that survive tend to do so by design rather than luck.

The island is Barro Colorado, a hilltop left standing when the canal was flooded. It is now a field station run by the Smithsonian Tropical Research Institute. Jacalyn Giacalone came there in the late 1970s to study red-tailed squirrels.

What grew out of that was much larger: a yearly dry-season count that she and her husband, Gregory Willis, began in 1982. They walk roughly 100 kilometers of fixed trail to record which mammals are on the island and how many. The route doesn’t change from year to year. That is the point. Walk the same lines the same way for long enough and the numbers start to mean something.

But the daytime walks had a blind spot. Some animals simply weren’t out when the counters were. Ocelots, the mid-sized spotted cats that move mostly after dark, kept slipping through. So in 1994 Willis added camera traps to catch the night animals the walks were missing. It is widely considered the first long-term system of its kind. The cameras kept improving, and the current network runs almost around the clock, building across the decades a picture of which mammals live on or pass through the island.

Cameras don’t just count. They recognize. An ocelot’s spots are as individual as a fingerprint, and with enough images you can tell one animal from another, then follow it across years. That is what makes the long run worth so much more than a short study: with ocelots, it buys generations. In 2017 the cameras first photographed an ocelot the team named Glitter alongside her three-month-old kitten, Globug. Following a mother, then her offspring, then that offspring’s offspring, is only possible if the watching never stops. Which, almost, it never did. Across the whole run, only 2021 was skipped, when COVID-19 kept the team from reaching Panama.

The century goal is plausible rather than wishful for one reason: the next pair of hands was already in the room. Claudio Monteza, now a postdoctoral researcher, had been helping with the project for years. During the pandemic he digitized old images and kept the cameras running. Back in 2023, he laid out the plan in his own words: “Since 2020 I have been working closely with Jackie Giacalone and Greg Willis, who carry out an animal census since the 1980s and 1990s, so that when I finish my PhD, I can continue the project.” That intention has since become the handover, a gradual process in which Giacalone and Willis stay involved rather than walking away all at once.

The target is 100 years, which lands in 2082. Think about what that number asks of a person. It asks you to plan past your own retirement, past your own life, and to spend years training successors long before you actually need them. Most careers are built to end with the person. This one is being built to survive the people in it. One counter teaching the next is the whole mechanism, which is how Giacalone and Willis became Monteza, and presumably how Monteza will become someone not yet born when the walks began.

Monteza’s first day leading the walks is the small thing that carries the large one. “During my very first day, I saw a Northern Tamandua using lianas to move from one tree to another,” he recalls, a single sighting rather than any claim about how anteaters usually get around. And it fell right where his own curiosity was heading. “It felt magical, especially because I am working on a proposal to study how mammals use lianas as pathways.” A project meant to run a hundred years starts again, for its newest keeper, with one animal crossing between two trees.