There are thought to be about 200,000 sperm whales in the world, but there is considerable uncertainty about the figure, which may be anywhere between 200,000-1,500,000 according to one site (1). The IUCN Red List states that the pre-whaling global population of sperm whales was about 1,100,000, so the number is probably much lower than that, in the hundred’s of thousands (2). It is surprising to me that there are no reliable estimates for this iconic animal. Perhaps it shows how little we still know about our oceans.
I had the good fortune to come across a few of these creatures on a voyage between Bali and Komodo (Indonesia) in October, 2016, on board a little ship called Mermaid I (3).
There are some phenomenal images of sperm whales on the Internet; just google it and you will see fantastic underwater photographs of these huge whales floating majestically below the surface. They are relatively shy creatures, so how divers get so close I don’t know, perhaps they are less wary of humans in the water, than of ships. Sperm whales live for up to 70 years, perhaps more, and sperm whaling was being carried out by Japan until 1988, so many of them may remember being perused and seeing their companions slaughtered. The Japanese are still killing Antarctic minke whales (4).
The first thing you see, as ever child knows, is the blow or outbreath. The Sperm Whale’s blow-hole is set at an angle on the left-hand side of its head; which causes the blow to shoot to the left (below).
It is very exciting when you come across a whale! The first one we saw was on the way to Satonda Island, north of the large island of Surabaya. Our small ship approached slowly so as not the frighten the whale, and we managed to get relatively close, although I was using a long lens (150-600mm).
Before we could get much closer however, the whale ‘turned tail’ and started to dive. The average dive apparently lasts for about 35 minutes and is usually ‘only’ down to about 400 m, although they can stay down for an hour or so and reach depths over 1,000 m (1). I guess it depends on what they find down there and whether they start chasing some prey item. Or perhaps they get into protracted fights with giant squids who do not relish being consumed by this giant predator of the depths!
After this whale had disappeared beneath the waves, we realised that there was a small one still at the surface: probably a calf. Females have a calf about once every five years and they stay together for several years. Perhaps this one was too young to start deep diving? Although it has to learn at some stage, and presumably gets lessons from the mother?
The next sperm whale we came across was in the open ocean south of the Komodo national park waters. Once again there was the tell-tail blow in the distance. Once again the ship slowed and approached the whale gradually, hoping it would not get spooked and dive down before we could see it.
This whale was a little bit more co-operative and we managed to get slightly nearer than the first one, but it too soon decided that enough was enough, and it dived down. Being behind it this time, we got a better view of the great tail fluke as it turned and dove in its majestic swoop.
I would like to have got better photos, but one gets what one is given, and I am grateful to have seen it. The last image is of the big flukes disappearing beneath the waves.
You don’t have to go all the way to Indonesia to see Sperm whales, they have a global distribution and are found around the shores of the United Kingdom. Indeed, there have been a number of high-profile stranding in recent years. Six sperm whales beached in Norfolk and Lincolnshire in 2016 (5). And a total of 29 stranding on the shores of the North sea as a whole in 2016.
Whilst there are records of these whales stranding as far back as 1577 (6), the fact that some of them have been found to have empty stomachs is very worrying. Especially, as the ones that beached in Germany, in Schleswig-Holstein, had stomachs which were filled with plastic debris (including discarded fishing nets) (7). Alas, we humans are fouling up this planet and the seas are filling up with plastic. It’s truly shocking. Unfortunately, it takes something like a dead sperm whale with a stomach full of plastic (or a dead albatross) to ram home the message that we are polluting the planet with our debris.
I am a retired entomologist with a background in quarantine pests and invasive invertebrates. I studied zoology at Imperial College (University of London) and did a PhD on the population dynamics of a cereal aphid (Metopolophium dirhodum) in the UK. I spent 5 years with the British Antarctic Survey studing cold hardiness of Antarctic invertebates and 17 years with the Food and Environment Research Agency. My main interests now are natural history, photography, painting and bird watching.