Giant fuck-off extinct doombirds: moa vs. Haast’s eagle
So moas, for those of you who don’t know/remember, were basically like a cross between a kiwi and an ostrich that could get to over 500 pounds.
They were really honking big, but some of that is sort of an optical illusion, since we’re pretty sure they didn’t run around with their necks all stretched out like that. They were herbivorous, and based on the way their vertebrae are lined up and connect to the skull, they probably had a posture more in keeping with the kiwi’s than a giraffe. They were hunted to extinction sometime in the 1400s, because humans found it way easier to kill way too many than their previous main predator, Haast’s eagle, had. Deprived of its main source of prey, Haast’s eagle followed shortly thereafter.
There are a few caveats before we start on this one. The first is that it took moas over a decade to reach their full size, and the second is that moas tended to be extremely sexually dimorphic. Like, there were moa species where it was so extreme they initially tried to classify the males and females as separate species before they realized what was going on.
So while moas could get to be over 500 pounds, most of the moas running around at any given time were probably a lot smaller due to their age and/or their sex. Even with this caveat, though, you need to be a really, really huge eagle to make it your business to hunt these things. Like, ostriches can only get up to 300 pounds, and pretty much the only things they have to worry about are cheetahs, lions, and hyenas.
Due to the huge size difference, Haast’s eagle probably killed a moa and then camped out for a few days eating it. I mean, a 33-pound eagle is nothing to sneeze at, but harpy eagles (biggest recorded specimen: 27 pounds) can only carry about half their body-weight, so we’re not talking about Haast’s eagle swooping down, snatching up a bird the size of a wildebeest, and flying off with it. Unfortunately. Because that would be both terrifying and hilarious. We’re talking more like the bearded vulture, where they attack things way bigger than them, kill them on site, and then eat them over a couple of days.
So, Haast’s eagle. Harpagornis moorei. We obviously never really got to measure and weigh a large specimen, because they died out before anyone thought that would be an advisable thing to do to a 30-pound murder-bundle. But based on their remains, they were also fairly sexually dimorphic, with males “only” getting to 20 pounds, and females’ wingspan topping out at 10 feet. This would actually have been kind of dinky for an eagle of that weight, but it’s an adaptation that we see in other big eagles who do most of their hunting in habitats with dense vegetation rather than soaring in open environments.
They rocked a beak-to-tail-tip length of about four and a half feet, though, which is bananas. Like, Philippine eagles, Steller’s sea eagles, harpy eagles, and golden eagles (the biggest living eagles) top out at a bit over three feet. The length may have helped compensate for the reduced wingspan without compromising maneuverability.
To put this in added perspective, here is some bird anatomy:
You’re looking for the tarsus, which is that bit of leg above their little feet.
In the harpy eagle (average weight: 22 pounds), the tarsus is about 5 inches long. In Haast’s eagle, the tarsus is 9 inches. This is what a harpy eagle’s horrible feet look like:
Steller’s sea eagle (average weight: 20 pounds):
Philippine eagle (average weight: 13 pounds), tarsus length of over 5 inches, seen here with future bird-murder victims:
So, Haast’s eagle was in all likelihood fully capable of murdering a human and absolutely nothing to fuck with.
[Picture: “Giant Haast’s eagle attacking New Zealand moa” byJohn Megahan]