If someone thinks of big cats swimming, they might picture a jaguar diving to catch a caiman in the murky waters of the Pantanal. Others might imagine tigers paddling amongst the mangroves of the Sundarbans. However, there is another species of big cat that has been documented swimming long distances — right here in the United States’ Pacific Northwest.
Washington State is home to a population of pumas, locally known as cougars. Panthera’s Olympic Cougar Project operates specifically on the Olympic Peninsula in the western part of the state, an area mostly covered by national park and forest land. Because they live on a peninsula, these cougars are threatened by growing development around the I-5 highway, which separates them from cougar populations elsewhere in the state. Such barriers to travel might place pumas at risk of low genetic diversity, which can jeopardize the long-term health of their populations.
Pumas that dive into the sea and swim diversify their avenues for potential dispersal, and often catch researchers by surprise! If we can predict where and when pumas choose to swim, we can better understand how they might disperse across landscapes with large bodies of water— and thus, how we can better protect them.
In early 2020, Panthera and partners with the Skokomish Tribe caught a young male cougar named Nolan and his mother on the Olympic Peninsula and marked them with GPS collars. After six months, he dispersed, and was tracked — you guessed it — swimming across the Puget Sound, an inlet of the Salish Sea separating the Peninsula from the mainland. And swim he did — for an astounding 1.1 kilometers — until he reached an island.
Based on this distance, we estimated that swimming pumas can gain access to 3,808 of the 6,153 islands surrounding Washington and British Columbia in the Salish Sea. We found 22 islands with records of confirmed cougar sightings between 1915 and 2020, 18 of which we predicted and four more of which required swims up to 2 kilometers! When we increased their potential swimming distance to 2 kilometers, they could access another 775 islands, for a total of 4,583 islands! We don’t know exactly how often these swims occur, but these cats can really get around!
This study reinforces data from Patagonia and other places in Latin America that shows pumas can indeed traverse large bodies of water. Importantly, it also demonstrates an often-overlooked mode by which pumas can disperse to connect with other puma populations. This is especially pertinent in more isolated populations like that on the Olympic Peninsula.
Nolan's story is just one #WildAtHeart tale. Donate to help wild cats like Nolan before Earth Day to support the ecosystems and communities these cats support. When we invest in wild cats, they invest in us.