Jaguar stuns scientists with longest swim ever recorded

Jaguars already carry a reputation as strong swimmers. What nobody expected was just how far one could go. In Brazil’s Serra da Mesa Reservoir, camera traps caught an adult male jaguar making the longest confirmed swim ever recorded for the species.

The journey covered at least 1.27 kilometers (0.79 miles) of open water. If the cat skipped a smaller islet along the way, the distance stretched closer to 2.3 kilometers (1.43 miles). Either option shattered previous records, which had topped out at just 200 meters (656 feet).

Record jaguar swim

The jaguar first appeared on camera traps along the mainland in 2020. Four years later, the same animal showed up again, this time on a forested island. Its coat pattern left no doubt about its identity.

Leandro Silveira from the Jaguar Conservation Fund noted that the team used a conservative estimate, assuming the jaguar paused on a smaller island before continuing. In reality, the animal might have swum the full 2.3-kilometer (1.43-mile) stretch in one go.

Big cats cross unexpected gaps

For years, hydropower reservoirs were seen as walls to big carnivores. Islands more than a kilometer (0.62 miles) away were often assumed unreachable, leaving them without top predators. Yet this swim tells a different story.

Reservoirs don’t always act as absolute barriers. Instead, they impose different costs depending on distance and conditions. Warm water, quiet surroundings, and an islet or two can lower those costs enough to let a jaguar cross.

Lions and cougars swim too

This isn’t the first big cat to push across long channels. Lions in Uganda’s Kazinga Channel have crossed distances of more than a kilometer, driven by the calls of females on the opposite bank.

In Washington State, cougars have braved cold, fast-moving waters to reach islands, sometimes swimming more than a kilometer (0.62 miles) in open channels.

These journeys highlight the determination of large carnivores when survival, reproduction, or territory expansion is at stake. Long swims may be rare, but when the incentive is strong enough, even top predators will take the risk.

Jaguars thrive in all terrains

Jaguars have always adapted to diverse environments. Some stalk prey in the Amazon floodplains. Others survive in the dry Caatinga with little water at hand.

Research using GPS collars has shown that jaguars can cover more than 120 kilometers (74 miles) in a month, even in areas shaped by human activity. The reservoir crossing adds to this evidence of resilience and adaptability.

A scale for crossings

A new framework ranks aquatic challenges on a simple scale. Short swims under 300 meters (984 feet) with islets fall into the low-cost category. Distances up to 1,000 meters (0.62 miles) with stepping-stones are considered medium cost.

Anything over one kilometer (0.62 miles) without help qualifies as high cost. The Serra da Mesa crossing lands firmly in the high-cost range but proves that jaguars can still manage.

Reservoirs impact jaguar survival

Hydropower projects have already submerged more than 25,000 square kilometers (9,650 square miles) of jaguar habitat.

The flooding converted continuous forests into scattered islands. In Venezuela’s Guri Reservoir, islands more than one kilometer (0.62 miles) from the mainland eventually lost their predators, which triggered ecological collapse.

The Brazilian record challenges that bleak picture. If conditions align, jaguars can bridge gaps once assumed permanent. Protecting riparian forests, keeping natural shorelines intact, and safeguarding small islands could all help create corridors that keep populations connected.

Primates in the water

The lesson doesn’t stop with jaguars. Primates in the Amazon have been observed swimming between islands, though only short distances.

Waterways that look like dead ends for land animals may instead be costly, but sometimes usable, filters. By planning for those possibilities, conservationists can keep ecosystems more intact even in reservoir-dominated regions.

Rethinking fragmented habitats

A jaguar swimming more than a kilometer (0.62 miles) across a dam reservoir forces a rethink. Water is not always an immovable wall. It can be a demanding path, but one that big predators can take. Recognizing these abilities changes how we view fragmented habitats.

Understanding when those paths open up, and what makes them possible, could shape how conservationists manage landscapes in a century marked by dams, development, and habitat loss.

It also raises questions about how often such events occur, how many animals attempt them, and whether these rare crossings can keep isolated populations connected over generations.

The study is published in the journal bioRxiv.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–