How heavy is a blue whale’s heart?

In the winter of 2014, at least nine blue whales from the endangered western North Atlantic population died in heavy sea ice in the Gulf of St. Lawrence. Two of the carcasses washed ashore in western Newfoundland that spring, one at Trout River and one at Rocky Harbour in Gros Morne National Park. The Royal Ontario Museum (ROM) took the skeleton of the Trout River whale and the heart of the Rocky Harbour whale.

Museum staff said the heart weighed more than 180 kg (about 400 lb), even when drained of blood and fluids, and was about the size of a large freezer. CBC News reported it as 5 ft (1.5 m) across, 4 ft (1.2 m) high and 3 ft (0.9 m) deep. Guinness World Records lists it as the largest heart, at 440 lb (199.5 kg) and about 1.5 m from the top of the aorta to the bottom of the lowest chamber. Either way it is nearly 600 times the weight of an average human heart, which is about 310 g.

It is the first blue whale heart ever preserved. ROM curator Mark Engstrom said he kept being asked how big a blue whale’s heart is, and the museum wanted a real one to point to. He also noted that, as in some other whales, the heart is symmetrical, unlike the asymmetrical human heart.

The heart was chilled, taken to Ontario and frozen for months, which left it flattened into a square shape. In June 2015 the team thawed it, plugged and sutured its many vessel openings, and pumped in six 189-litre drums of formalin to inflate it back to its natural shape and stop it from decaying.

In November 2015 it was drained, wrapped, and flown on a Lufthansa cargo plane to Germany for plastination, the method invented by anatomist Gunther von Hagens. In plastination the water in the tissue is replaced with acetone, and the acetone is then replaced with a silicone polymer in a vacuum chamber, so the finished heart is largely silicone in the exact shape of the original. It arrived back in Toronto on 15 May 2017 and was installed three days later in the exhibition Out of the Depths: The Blue Whale Story.

In 2019 Jeremy Goldbogen and colleagues recorded a blue whale’s heartbeat for the first time, using a suction-cup tag on a male of about 23 m in Monterey Bay, California. During dives the heart beat 4 to 8 times a minute, and as slowly as 2 beats per minute. Back at the surface it raced to 25 to 37 beats a minute, close to the roughly 33 bpm the authors estimate as its upper limit.

Using scaling formulas from other mammals, the same paper predicts that a 70,000 kg whale has a 319 kg heart pumping about 80 litres of blood per beat. That is an estimate, not a measurement, and it is well above the 180 kg weighed for the ROM heart. Guinness gives a larger figure for the blood pumped, about 220 litres per beat.

No. The old claim that a blue whale’s heart is the size of a Volkswagen Beetle did not survive the ROM’s dissection. Engstrom told CBC News in 2015 that the heart is big but smaller than people had suggested, not quite as big as a Volkswagen. A Beetle is about 14 ft long and weighs around 3,000 lb, several times the heart’s size and weight. The ROM’s own touring exhibition brochure still compares it to a Smart car, which still overstates it.

The idea that a person could swim through its arteries is also an exaggeration. A photographer who documented the work for the ROM wrote that the largest valve opening was one she could squeeze her head through. That is a huge blood vessel, but nowhere near wide enough for an adult to swim along it.