Sunday, January 2, 2011

Monsters Part 2: Giant Eagles and Mega Sharks

After our look at my favourite Australian monsters, I thought I’d have a look at my two favourite monsters from the time after the dinosaurs dies. These are namely the megalodon, a huge sharked that roamed the oceans, and the Haast’s Eagle, a massive predatory bird from New Zealand.


Firstly, let’s stay dry and have a look at this massive eagle. Haast’s Eagle would have been a truly terrifying sight to behold, especially since it only went extinct around 600 years ago. In fact, the Māori have a legend about this fearsome bird, known to them as the Pouakai, a bird-monster who ate humans. And, when you find out how big this thing was, and what it ate, it’s not hard to believe in that little myth.


Haast's Eagle about to catch dinner

This flying monster stood about 90cm tall and weighed between 9 and 15kg. Now, that may not sound like much, but this thing would fly at 80km/h! Anything travelling at those speeds demands respect. Also, they hunted moa, New Zealand’s version of the emu or ostrich. The only thing is moas were much larger than their Australian or African equivalents, reaching some 230kg themselves, some 15 times the weight of the Haast’s Eagle. The fact that this predator would take something like that down is really cool.


Haast’s Eagle had a wingspan of about 3m, on par with the largest of the Golden Eagles or Stellar’s Sea Eagles, but even the biggest of these don’t get much more than half the weight of the Haast’s Eagle. It also had rather powerful legs, able to get into flight from a single jump, quite a feat for such a large bird (think of how a pelican gets into flight, and they max out at bout 13kg). The Haast’s short, strong wings were probably a benefit when hunting through the dense scrub and woodland of New Zealand. So, not only was its size amazing, but it probably was also a very agile bird. Running into a forest wouldn’t save you from this giant.


When hunting moa, the eagle would sit on a perch and stay motionless for a while until a suitable moa came along. It would then rapidly soar down and grip the moa near the pelvis with one taloned foot, whilst the other would kill the animal with a swift strike to the head or neck. This strike would have been equivalent to that from a brick which has fallen some 8 stories, quite a punch. Obviously, this 15kg bird can’t eat a whole 230kg moa in a single sitting, so it would use the same carcass for several days, and stay nearby.


Haast's Eagle and two Moa

One of the most amazing things about this bird is how recently it went extinct. The Māori didn’t reach New Zealand until about 700 years ago, and they rapidly wiped out the moa, the Haast’s main food source. It is completely likely that the Haast’s did kill and eat people, especially since we are a lot smaller than the big moas, so the legend of the Pouakai would suggest that the Māori did have contact with this eagle. But, if humans didn’t get to New Zealand until recently, it is more than likely that we would still be able to see this great, majestic beast in all its glory. Because the Māori hunted the Moa into extinction, the Haast’s Eagle could not find food, so went extinct itself.


If you’re scared of sharks, you might want to skip this bit, or you might be kept up at night.


Put your hand up if you’ve seen Megashark vs. Giant Octopus. I can’t see your hands... probably because I’m not exactly looking at you, but hey. If you haven’t, I suggest you get a couple of like minded friends, a bottle of your chosen beverage (mine’s wine) and watch the pants off this movie. It has the absolutely most terrible depiction of my next monster, megalodon.


So, you think Great Whites can get pretty big, huh? 6m is a rather large fish, hey? Well, between 25 and 1.5 million years ago there was a shark which made the Great White look like the fish you catch off the pier. Megalodon (Greek for big tooth) topped the scales at about 105 tons and a length in excess of 20m. This fish could literally swallow you in a single gulp.


Megalodon tends to make you feel small and insignificant

This fish, like many sharks, had 5 rows of teeth, but these teeth were over 18cm long. They are shaped much like great white teeth, but are more robust. This, coupled with the great size of the shark, allowed it to bite down with a maximum force of over 18 tons! That’s like having a rather large truck drive into you, and all focused along those teeth. It probably wouldn’t hurt; there wouldn’t be time for that.


So, we have a really big shark, so what would it eat? Well, whales are pretty big, aren’t they, so it could have eaten them. And true to form, there have been many different whale fossils found with tooth marks which match those of megalodon. There have also been several teeth found near fossils, so that adds to the idea that this giant shark ate whales. But, it didn’t stop there. It was probably a pretty opportunistic hunter, taking what it came across, such as seals, dugongs and manatees and even large sea turtles. It would also have eaten other fish, and possibly ate other megalodons. They could swim at high speeds, so chasing prey wasn’t a problem, and they are thought to have been rather smart predators too.


From evidence of whale fossils, megalodon probably tried to immobilise its prey by biting its fins and tail, or crushing its vital organs. It could also have acted similar to great whites when hunting seals, and attacked by ramming smaller prey from below at great speed. It kind of adds something to those images of great whites flinging seals into the air. Imagine an airborne whale!


I love it when these guys play with their food

Try this on for size. Megalodon could inhabit pretty much any marine environment. It’s thought that they had their nurseries in shallow coastal waters, and moved out into more open water as adults. Whilst it probably wouldn’t have gone up to the Polar Regions, it would have inhabited most temperate and tropical oceans, much like the great white today. This is possibly one reason it began to go extinct. As the globe cooled over the last few million years, water temperature dropped too, forcing megalodon to more equatorial latitudes. A cooling globe would also reduce the available nurseries for this beast, limiting its ability to repopulate. It also could have lost out like the Haast’s Eagle and lost its food supply, or may have been out competed by the emerging Orca. Anyways, I’m kind of glad it’s extinct, it was a true monster.


A truly terrifying beast

Next week, I’ll take a look at Nessie’s cousins and a similar predator from the time of the dinosaurs. As always, if you have comments questions or suggestions, please email me!


  1. For some reason the first paragraph looks all funny. I'm trying to work out how to fix it, but if you think you can help, please email me at

  2. Its a pity New Zealand has the Kiwi as it's national bird.
    The small, flightless, extinct if not for human intervention worm eating bird versus the almighty death from above winged beauty that was the Haast Eagle. I know which one i'd prefer.