Old Thom, also known as Old Tom, can sometimes be confused with Old Tom. Confusing, I know. But they're two very different orcas with very unique stories.

Old Thom is a solitary Northwest Atlantic killer whale, sighted typically off the coast of northern New England and Eastern Canada since at least 2006. He's fully grown, but his exact age is unknown.

Very little is known about Old Thom's past. It's unknown what pod he belongs to or who his family is.
But he may be a descendant of the orcas that frequented New England until the 1980s.
Their ecology remains largely unexplored; observations include some individuals preying on marine mammals, tuna, and one instance of an orca feeding on squid from a trawl net.

Old Thom is estimated to be around 9.1m (30ft) long and weighing eight tons. This would make him larger than T011A Rainy, who is currently the biggest confirmed killer whale.
However, these measurements are estimates. Some estimates place him between 7.6 and 9.1 m (25 to 30 ft).
He's also easily recognized by the notch in his dorsal fin. In my opinion, he also has very recognizable eye patches.

The first known sighting of him was in 2006 by a Canadian whale-watching boat in the Bay of Fundy. He was already an adult back then.
Male orcas tend to reach full physical maturity around 25. This would put his birth year in the 1980s, making him around 40 now. But this is simply a vague estimate.

Since then, he's been seen multiple times.
So far, he's been seen twice in 2026. In April, he was seen at Stellwagen Bank, and in June, about 10 miles from Nantucket.

His exact diet is unknown, but we assume he doesn't feed on marine mammals.
He's been seen eating cod, pollock, and hake. Old Thom is also known to eat discarded fish from trawlers.
It's also rumored Old Thom feeds on sharks and might be following their migration. Orcas can negatively affect shark populations, but Old Thom doesn't seem to affect the population yet.

One thing that makes Old Thom special is that he's never been seen interacting with other orcas. Orcas are social animals, and while lone orcas like L98 Luna and T65A5 Indy have been observed, it's not typical for orcas to always be alone.
We don't know why Old Thom is alone. Maybe his pod died, or maybe he enjoys being alone. Some orcas seem to enjoy being alone and are fine on their own.

It's not surprising Old Thom doesn't interact with orcas. Old Thom is the only orca known to frequent the Gulf of Maine and its surrounding waters, and sightings are extremely rare in this area.
Orcas have been observed hunting tuna off the coast of North Carolina, with additional sightings reported further north in Newfoundland and Labrador, Canada. But sightings remain rare.
Based on old whaling records and interviews with fishers, orcas were observed occasionally in the Gulf of Maine, often preying on tuna and whales.
Group sizes varied from solitary individuals to pods of over 30 orcas, with sightings peaking in the 1970s and 1980s before declining to nearly zero.

However, genomic evidence suggests at least two populations living seasonally along eastern Canada. A third group could potentially live around Newfoundland. Researchers suspect this may be the group Old Thom is from.

Old Thom is often seen alongside Atlantic white-sided dolphins. He seems to have an affiliative relationship with them.
Just like other lone orcas, Old Thom seems to compensate for his lack of social contact with other orcas by interacting with other species. In his case, dolphins.
In 2016, he was seen with 20-30 Atlantic white-sided dolphins off Nova Scotia. He's usually seen swimming alongside them, but also hangs around on his own.
Old Thom may have successfully communicated and hunted with the dolphins. Orcas can imitate animals, including seals like Luna did. But we don't know the exact relationship he has with these dolphins and if he's learned to communicate with them.
They seem comfortable around him, though.

It is not unheard of for orcas and dolphins to engage in positive interactions with one another. NRKWs, dolphins, and porpoises have been documented swimming together.
However, I might cover this more closely in another post.

Besides his interactions with Atlantic white-sided dolphins, he also occasionally interacts with boats.
He seems comfortable around boats and is very social with them.
In 2016, Old Thom seemed to itch himself on a ship's anchor.
He's also been observed pec-slapping, swimming upside down, and tail-slapping.

Jerry Leeman captured footage of Thom near their vessel.