Humpback Whales

I’d never seen a whale before we came to Australia – although various species do come into UK waters there aren’t many opportunities to see them. However there are lots around Australia – in particular humpback whales as they migrate up both east and west coasts from the Antarctic to the tropics to breed, and then go back again – up to 25,000km in a year (that’s an average of 68km a day!). I’ve only seen humpbacks, but you also get right whales and blue whales down on the south coast. As is so often the case with wildlife spotting it’s all about being in the right place at the right time (and looking the right way!) – but the internet can really help with this.

You could write books and books about whales (and of course many people have), from the science of their fascinating natural lives through to the complex interactions with humans, who did their best to wipe them out but happily seem to be largely trying to get along nowadays. I’m not going to try to cover this vast range of information, but instead say a few things about humpbacks, and try to dig out some interesting facts you might not know.

My first whale watching trip was from Hervey Bay up near Fraser Island. It’s a great place to go whale watching – nice and warm, and Fraser makes a good backdrop:

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Anyway, before we got to that tail, and as we set off excitement was pretty high as you might imagine. The first whales were spotted by the captain, and he moved the boat towards them. There are pretty strict regulations about how close you can get to whales and dolphins, and from what I’ve seen these are well respected, but humpbacks are curious creatures and will often come over and investigate boats. So I was well chuffed to look down and see my first whale just sitting there, right underneath the boat:

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After clicking away from different angles and marvelling at my luck, I eventually started to wonder why the whale was quite so still, and finally realised I’d been taking pictures of the protruding keel of the boat. Doh!

Another time we really did get one swimming right under the boat – here it is approaching:

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…and then it briefly surfaced before diving. I’d always thought whales’ blow holes were just that – a single hole – but as you can clearly see here it’s much more like a backwards-facing nose. However unlike our noses whales can close theirs when diving.

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Let’s take a step back though. Humpbacks are large whales – they get up to 16m long and 36 tonnes, although the biggest blue whales probably get up to 30m and over 180 tonnes. It’s difficult to compare with dinosaurs, as fossils of the largest sauropods are fragmentary, but argentinosaurus has been estimated at 40m long and 95 tonnes. The largest tyrannosaurus (called Sue) was 12.3m long, and up to 14 tonnes. So even though humpbacks aren’t quite in the very top echelons of big beasts, they’re definitely in the megafauna premier league and substantially larger than any terrestrial animals.

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How do they get that big? They eat a lot of krill, about 2-2.5 tonnes a day during the feeding season – they fast on the way up and back from the tropics. When I was younger I assumed that zooplankton (which includes krill and many other little beasties) was pretty tiny – microscopic to a few mm. Actually krill are typically up to 2cm long, and some species are up to 15cm, which is small prawn-size in my book. Humpbacks will also eat small fish, such as juvenile salmon or herring etc. And humpbacks are not shy about doing this, either – they charge into schools of fish and take great gulps of water. They can gulp up to 19,000 litres at a time, so don’t ever offer to buy a whale a drink! This balloons out their flexible cheeks and then they use their baleen to filter out the water and keep the fish. Sometimes they get together and blow rings of bubbles to surround fish, and then swim up the middle to scoff them all.

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It’s estimated that there are about 379,000,000 tonnes of krill in the Antarctic, which is a fair bit more than the estimated total human biomass of 350M tonnes. In fact it’s thought to be one of the highest biomasses of any single species – domestic cattle beat it at 520M tonnes, and surprisingly earthworms come in at up to 7,600M tonnes. That’s an awful lot of worms! Anyway it’s certainly plenty of krill for the whales – there are an estimated 50,000 humpbacks in the southern hemisphere, and another 30,000 in the northern (the pre-whaling estimate is 125,000, and hopefully we might regain that one day).

 

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Humpbacks are sociable creatures, and communicate in a number of ways including singing. Their songs can be up to 30 minutes long, but we don’t know the exact purpose. I like to think that maybe they just enjoy it. They also breach (jump up out of the water) – I’ve seen this once, but completely failed to get a picture of it – however many others have. If you’re on a boat next to one doing this you are going to get seriously wet! Humpbacks also like to slap the water with their tails, and I’ve got plenty of pictures of this. Again, this seems to be for communication of some sort, but no-one knows what yet. However because of the significant energy expended in both breaching and tail-slapping it’s thought it must mean something – they can’t just be having fun, can they?

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All humpbacks have unique tails, and the pattern of notches, angles, scars and barnacles etc means you can use this to identify them. That’s particularly useful as it’s easier to get a picture of the tail than many other parts of them! I’m afraid I have no idea if the whale above has been identified – unfortunately it seems that people are still better than computers at matching tails, and it’s a really boring job!

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To finish with I’ll share my closest encounter with a whale. We stopped off for a couple of days at Noosa on the way back from Fraser Island – it’s a nice place, a little commercialised but not unpleasantly so. But because it’s a bit commercialised that means powered water fun, and Felix was desperate to have a go on a jet ski. Can’t say I found the idea unappealing either, although it’s definitely not Elliot or Ginny’s thing. So Felix and I hired one and off we went, through the lagoon and then out to the sea. We knew there were whales around and were keeping our eyes open, but hadn’t spotted any. Felix was driving the jet ski around, and tried doing doughnuts, spinning it around. I was on the back, and as it went around and around in tighter circles it leaned more and more. Eventually it leaned so much I couldn’t hang on and fell off the side, whereupon the jet ski straightened up and Felix powered off, cackling with glee. What neither of us had realised was there was a huge humpback swimming very close to us. Felix slowed down and I swam over to him, and we saw the whale briefly surface before it cruised off. I dined out on the story of my own son dumping me in front of a whale for ages…

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