How much does a whale weigh?

2019/10/10 Roa Zubia, Guillermo - Elhuyar Zientzia

• Matematika

Those who communicate the number may not know whether the number is correct or not. In the case of the Eiffel Tower, yes, there are plans and we know the number of pieces and the size and weight of each of them, but we have to take into account thousands of factors. In the case of the Amazon, it is clear that no one has counted those trees. What we have to keep in mind is that all those gigantic data that we are told is a calculation, an approximation. And that two approximations of the same data do not give the same result.

A news from the BBC says: “How to weigh a voucher without using a scale.” True, how much does a whale weigh? It is the same who answers that question; the number that says is an estimate. A calculation is not a correct or exact result. Those of the BBC say that it is not possible to weigh a voucher, unless the corpse has been found on the beach. And even so, one cannot weigh. You can make an estimate with nearby data, measure length, etc., but there is no balance that weighs that body.

Now. Estimates and approximations can be made in many ways. And there comes what they tell in the news of the BBC. The case is that researchers from Denmark have started using drones to calculate the weight of the whales. Researchers from the Aarhus Institute of Advanced Research. The drones make photos. Many and good photos. And above all, they are photographs of live animals. And from these photos you can guess the dimensions of the whales. Hence, knowing the muscular, bone density, etc. From the whale, you can calculate the weight. Since we do not know the actual weight, of course, we cannot know to what extent that calculation is accurate. But it is logical to think that this method is one of the best we have until today to know the weight of a whale.

In passing, the calculation of the weight of the whale serves for its conservation. If you see a single copy again and again, you will have an evolution in time that can provide interesting information for conservation experts.

But one last thing, how much does a whale weigh? The answer is correct, we do not know. But well, we have an approximation and we believe it is not very bad. The weight of a blue whale is approximately 190 tons.